Broadband,high-sensitivity self-powered ferroelectric LuMnO3-based photodetector with large photocurrent output

The broadband spectrum detection from ultraviolet to near-infrared is hankered in the photoelectric applications of imaging, sensing and communication. Here, a new self-powered photodetector based on ferroelectric LuMnO₃ thin film with a narrow bandgap of 1.46 eV exhibits high-sensitivity ultraviolet–visible–near infrared photodetection properties. The responsivity (R) and detectivity (D*) in sunlight are 0.4 A/W and 7.05 × 10¹¹ Jones, which are much higher than that of other ferroelectric photodetectors. Moreover, under the monochromatic light (900 nm), the R and D* can reach 0.39 A/W and 6.89 × 10¹¹ Jones. The outstanding photodetection performances owed to the large photocurrent output, where the short-circuit current density can reach 10.5 mA/cm² under 1 sun illumination. The synergistic effect of ferroelectric photovoltaic effect and interface barrier effect demonstrates that the multi-driving forces can achieve high dissociation efficiency for photon-generated carriers. The excellent photodetection performances open up new application of ferroelectric materials in broadband self-powered photodetectors.     

The suppression of dark current for achieving high-performance Ga2O3 nanorod array ultraviolet photodetector

Gallium oxide (Ga₂O₃) is a promising candidate for next-generation solar-blind photodetectors (PDs) because of its large bandgap of 4.9 eV. Its single-crystal nanorod structure improves its photoelectric performance, which promotes carrier transformation and separation. However, Ga₂O₃ nanorods fabricated by the hydrothermal method have many oxygen vacancies, which largely enhance the dark current and reduce the on/off ratio of PDs, restricting application of such devices. Therefore, in this paper, dual strategies are applied to reduce the dark current of a metal–semiconductor–metal-structured Ga₂O₃ nanorod PD fabricated by the hydrothermal method. Through these dual strategies, which include annealing treatment and the application of a polymethyl methacrylate (PMMA) coating, the dark current of the PD is reduced from 1.34 × 10^?7 to 2.04 × 10^?9 A at 1 V, resulting in the on/off ratio of the PD reaching as high as 3.24 × 10⁴. Besides, the responsivity and detectivity of the device reach 1.73 A/W and 2.53 × 10¹² Jones respectively, which represents better performance than those of other reported Ga₂O₃ nanorod array PDs. Results have shown that the new strategy adopted can greatly improve the performance of Ga₂O₃-based ultraviolet photodetectors.     

Enhanced pressure-driven force-electric conversion effect for (Pb,La)(Zr,Ti)O3 ferroelectric ceramics

The pressure-driven force-electric conversion materials with extremely rapid response time have been widely used in mining, defense, and energy areas. The discharge process by the force-electric conversion effect in ferroelectrics is dominated by polar-nonpolar phase transformation. In this work, (Pb_0.985La_0.01)(Zr_xTi_1-x)O₃ (PLZT, x = 0.85–0.94) ceramics is designed by tunning Zr⁴⁺/Ti⁴⁺ ratio and aliovalent La doping to achieve high remnant polarization (P_r) and excellent temperature stability. We focus on the pressure-driven depolarization in PLZT ceramics, and their corresponding phase structure, ferroelectric properties, dielectric properties, and thermal depolarization. In PLZT (x = 0.93) ceramics, the original polarization P₀ increases to 43.42 μC/cm². The pressure-driven depolarization releases 37.66 μC/cm² with the depolarization proportion of 86.73%, which is attributed to irreversible ferroelectric-antiferroelectric phase transition. It also exhibits excellent temperature stability up to 120°C (> 36 μC/cm²). This work provides a high-performance alternative to Pb(Zr_0.95Ti_0.05)O₃ and guidance for the development of pulse power energy conversion devices.     

Fast response and broadband self-powered photodetectors based on CZTS/SiNW core-shell heterojunctions for health monitoring

In this work, fast response and broadband self-powered photodetectors based on heterojunctions of vertical smooth silicon nanowires (SiNWs) were proposed, which were achieved through spin-coating p-CZTS on top of n-SiNWs adopting a simple two-step method. First, CZTS was uniformly and tightly attached to the sidewalls of SiNWs in the form of nanoparticles. The prepared CZTS/SiNWs core-shell heterojunctions exhibited typical rectification characteristics in dark and excellent light response characteristics in light illumination. Our device could perform self-driven detection under the UV-VIS-NIR light irradiation without an external energy supply. The responsivity and specific detectivity were estimated to be 14 mAW^-1 and 1.5 × 10¹¹ Jones, which can be improved to 0.35 AW^-1 and 1.2 × 10¹³ Jones at ?1.5 V bias. In addition, the present device also possesses distinct advantages of a large I_light/I_dark ratio exceeding 4.25 × 10⁴, fast response rate with rise/fall times of 1.4/14.2 μs, and outstanding environmental stability. Finally, a heart rate health monitoring application by CZTS/SiNWs detector was proposed. All these results may pave a way for the real application of the self-driven detector in the field of health monitoring in the future.     

Enhanced magnetic,ferroelectric, and photocatalytic properties of (1-x)BiFeO3-xBaTiO3 (0.0 ≤ x ≤ 0.4) powders

The magnetic, ferroelectric, and photocatalytic properties of (1-x)BiFeO₃-xBaTiO₃ (0.0 ≤ x ≤ 0.4) powders synthesized by sol-gel method have been investigated. X-ray diffractometry confirms that the phase of the samples changed from rhombohedral to cubic with the increase in BaTiO₃ content. The grain size decreases and the particle shape becomes homogeneous with the introduction of BaTiO₃. BaTiO₃ substitution enhances the multiferroic properties of the ceramics and the maximum remnant magnetization (0.261 emu/g) and remnant polarization (20 μC/cm²) have acquired in 0.8BiFeO₃-0.2BaTiO₃ and 0.7BiFeO₃-0.3BaTiO₃, respectively. The absorbance in ultraviolet and visible light regions is improved obviously for powder with x = 0.3. The energy band gap of the samples decreases from 2.06 eV to 1.57 eV with the introduction of BaTiO₃, indicating that the excitation rate of photogenerated electron-hole pairs is improved. The highest methylene blue degradation efficiency of ~62% within 3 h under the visible light is achieved in the 0.7BiFeO₃-0.3BaTiO₃ which can be attributed to its suitable energy band gap and large remnant polarization.     

Self-powered broadband α-MoO3/Si photodetector based on photo-induced thermoelectric effect

As a two-dimensional crystal, molybdenum trioxides (α-MoO₃) has been considered as a typical candidate for next-generation photodetectors (PDs) but with limited photodetection applications in the ultraviolet region. Here, a photo-induced thermoelectric (PTE) effect in α-MoO₃ is proposed as a practical approach to realize the broadband photodetection of α-MoO₃/Si heterojunction PDs. High-quality α-MoO₃ films are grown on Si by using an e-beam evaporation method. By modulating the photo-induced thermoelectric potential along the c-axis on the transport properties, the α-MoO₃/Si PDs can be operated as a self-powered device, showing broadband photoresponse beyond the bandgap limitation in the wavelength range of 405–1550 nm. The manipulation of the PTE effect in the heterojunction is investigated carefully, clarifying the corresponding physical mechanisms of the unique photoresponse behaviors. Furthermore, the fabricated device exhibits competitive photodetection performance with a high photoresponsivity of 63.3 mA/W, a high optical detectivity of 3.1 × 10¹¹ cm Hz^1/2W^?1, fast response speeds with the rise/fall times of 0.47/0.76 ms, as well as high durability and environmental stability under 980-nm infrared illumination. These results not only provide a novel strategy to develop novel PDs with high performance, but also supply a deeply understanding of the PTE effect in α-MoO₃/Si heterojunctions.     

Structural,Electrical, and Ferroelectric Properties of Nb‐Doped Na0.5Bi4.5Ti4O15 Thin Films

Ferroelectric Na_0.5Bi_4.5Ti₄O₁₅ (NaBTi) and donor Nb‐doped Na_0.5Bi_4.5Ti_3.94Nb_0.06O₁₅ (NaBTiNb) thin films were prepared on Pt(111)/Ti/SiO₂/Si(100) substrates using a chemical solution deposition method. The doping with Nb⁵⁺‐ions leads to tremendous improvements in the ferroelectric properties of the NaBTiNb thin film. Room‐temperature ferroelectricity with a large remnant polarization (2P_r) of 64.1 μC/cm² and a low coercive field (2E_c) of 165 kV/cm at an applied electric field of 475 kV/cm was observed for the NaBTiNb thin film. The polarization fatigue study revealed that the NaBTiNb thin film exhibited good fatigue endurance compared with the NaBTi thin film. Furthermore, the NaBTiNb thin film showed a low leakage current density, which was 1.48 × 10^?6 A/cm² at an applied electric field of 100 kV/cm.     

Ultraviolet photodetectors based on ZnO nanorods-seed layer effect and metal oxide modifying layer effect

Pt/ZnO nanorod (NR) and Pt/modified ZnO NR Schottky barrier ultraviolet (UV) photodetectors (PDs) were prepared with different seed layers and metal oxide modifying layer materials. In this paper, we discussed the effect of metal oxide modifying layer on the performance of UV PDs pre- and post-deposition annealing at 300°C, respectively. For Schottky barrier UV PDs with different seed layers, the MgZnO seed layer-PDs without metal oxide coating showed bigger responsivity and larger detectivity (D _λ*) than those of PDs with ZnO seed layer, and the reason was illustrated through energy band theory and the electron transport mechanism. Also the ratio of D ₂₅₄* to D ₅₄₆* was calculated above 8 × 10² for all PDs, which demonstrated that our PDs showed high selectivity for detecting UV light with less influence of light with long wavelength.     

Preparation and characteristics study of self-powered and fast response p-NiO/n-Si heterojunction photodetector

The growth of crack-free nanostructured NiO films with good crystalline quality is of high importance for photodetectors to avoid performance failure. In this work, physical properties of spin coated NiO films were controlled by changing diethanolamine (DEA) to nickel acetate (NiAc) molar ratio (0:1–1:1) and post annealing temperature (300–650 °C). NiO film coated at DEA:NiAc molar ratio of 0:1 suffered from severe cracks and poor crystallinity, and by increasing the molar ratio to 1:1 a crack-free NiO with enhanced grain growth was obtained. With the increase of annealing temperature from 300 C to 600 °C, the crystallite size increased from 12.79 to 37.31 nm, and the bandgap decreased from 3.81 to 3.42 eV, indicating an enhancement in NiO film quality. A self-powered photodetector based on p-NiO/n-Si heterojunction showed broadband (UV-NIR) photodetection owing to synergistic photoelectric effect from both NiO film and Si substrate. The responsivity, detectivity, and external quantum efficiency were measured as 13.08, 46.02, 44.49, mA/W, 1.03 × 10¹¹, 3.65 × 10¹¹, 3.53 × 10¹¹, Jones, and 4.43%, 8.62%, 6.47% upon illumination with UV (365 nm), red (660 nm), and NIR (850 nm) lights, respectively. The photodetector showed high on/off current ratio of 1.210 × 10³ and fast response (less than 85 ms). These findings introduce p-NiO/n-Si heterojunction as a promising candidate for next generation optoelectronics.     

Induced slim ferroelectric hysteresis loops and enhanced energy-storage properties of Mn-doped (Pb0·93La0.07)(Zr0·82Ti0.18)O3 anti-ferroelectric thick films by aerosol deposition

In this study, the high ferroelectric hysteresis loss of (Pb_0·93La_0.07)(Zr_0·82Ti_0.18)O₃ (PLZT 7/82/18) antiferroelectric (AFE) ceramics was reduced by employing a combinatorial approach of Mn acceptor doping followed by thick film fabrication via an aerosol deposition (AD) process. The grains of the as-deposited PLZT 7/82/18 AFE AD thick films were grown by thermal annealing at 550 °C to enhance their electrical properties. Investigation of the electrical properties revealed that Mn-doping results in improved dielectric and ferroelectric properties, increased dielectric breakdown strength (DBS), and energy-storage properties. The Mn-doped PLZT AFE AD films possess a frequency-independent high dielectric constant (ε_r ≈ 660) with low dielectric loss (tan δ ≈ 0.0146), making them suitable candidates for storage capacitor applications. The bipolar and unipolar polarization vs. electric field (P-E) hysteresis loops of PLZT 7/82/18 AFE AD thick films were found to be slimmer than those of their bulk form (double hysteresis) with significantly reduced ferroelectric hysteresis loss, which is attributed to the AD-induced mixed grain structure. The Mn-doped PLZT 7/82/18 AFE AD thick films exhibited a low remnant polarization (P_r ≈ 9.22 μC/cm²) at a high applied electric field (~2750 kV/cm). The energy-storage density and energy efficiency of the Mn-doped PLZT AFE AD thick films were calculated from unipolar P-E hysteresis loops and found to be ~38.33 J/cm³ and ~74%, respectively.     

Structures and pyroelectric properties for [111]-oriented Mn-doped rhombohedral 0.36PIN-0.36PMN-0.28PT crystal

The crystal structures, pyroelectric properties, and thermal stability of [111]-oriented 0.5 mol% Mn-doped 0.36Pb(In_1/2Nb_1/2)O₃-0.36Pb(Mg_1/3Nb_2/3)O₃-0.28PbTiO₃ (Mn-0.36PIN-0.36PMN-0.28PT) ternary single crystal were investigated. The temperature dependence of the Raman spectra and dielectric properties revealed that the crystal exhibited a rhombohedral (R) structure at room temperature, and ferroelectric R → tetragonal (T) and ferroelectric T to paraelectric cubic (C) phase transitions at 130 and 175°C respectively. The single crystal had a high remnant polarization of P_r = 38 μC cm^–2 and coercive field of E_C = 12 kV cm^–1 at room temperature and a frequency of f = 100 Hz. The values of P_r and E_C decreased with increasing temperature, exhibiting anomalies near their phase-transition temperatures, which coincided with changes in the Raman spectra and dielectric properties. Furthermore, at 25°C and f = 100 Hz, the single crystal had high pyroelectric coefficients of p = 8.7 × 10⁻⁴ C m⁻² K⁻¹, figures of merit for the current responsivity of F_i = 3.5 × 10⁻¹⁰ m V⁻¹, the voltage responsivity of F_v = 0.08 m² C⁻¹, and the detectivity of F_d = 30.1 × 10⁻⁵ Pa^−1/2. These values were weakly dependent on temperature below 120°C. In addition, the room-temperature pyroelectric coefficients of the ternary single crystal maintain over 83% of the original value at thermal annealing temperatures below 120°C. These outstanding pyroelectric properties, together with high thermal stability, indicate that [111]-oriented rhombohedral Mn-0.36PIN-0.36PMN-0.28PT ternary single crystal is a new potential candidate for infrared detection applications.     

Influence of LNO Top Electrodes on Electrical Properties of KNN/LNO Thin Films Prepared by RF Magnetron Sputtering

Highly (001) oriented (K,Na)NbO₃ (KNN) lead‐free piezoelectric thin films were grown on LaNiO₃ (LNO)‐coated silicon by RF magnetron sputtering. The effects of the top electrodes on the electrical properties of KNN thin films were investigated. The dielectric and piezoelectric properties were remarkably improved in LNO/KNN/LNO (ε_r = 899 at 1 kHz, d₃₃ = 58 pm/V), compared with that in Pt/KNN/LNO (ε_r = 584 at 1 kHz, d₃₃ = 26 pm/V). An enhanced ferroelectricity was also obtained in LNO/KNN/LNO, with a remnant polarization of 12 μC/cm² and a maximum polarization of 23 μC/cm² at the applied field of 200 kV/cm. Besides, the temperature dependence of piezoelectricity of the films was characterized in this study.     

Artificially induced ferroelectric-like behavior in an antiferroelectric sandwich structure by interface engineering

Interface engineering is essential for achieving fascinating interfacial functionalities in a single all-oxide-interface-based device. In the present work, a sandwich structure (Pb_0.94La_0.06(Zr_0.95Ti_0.05)O₃ (PLZT)/HfO₂/ Pb_0.94La_0.06(Zr_0.95Ti_0.05)O₃) was fabricated via a chemical solution approach. A distinct “ferroelectricity-like” behavior with high P_max (～ 80 μC/cm²) and P_r (～ 36 μC/cm²) is demonstrated. The dielectric HfO₂ thin layer presents a tetragonal symmetry structure, which stabilizes a slight distorted structure of the upper PLZT layer (PLZT(T)) with a= 4.19(9) Å, b= 4.10(6) Å, β ～ 91.04?. In PLZT(T), the ferroelectric (FE) phase is identified as the matrix embedded with a small amount of AFE nanodomains, while the bottom PLZT layer (PLZT(B)) exhibits typical AFE incommensurately modulated structures. The near-interface structures in both PLZT layers are characterized by ferroelectric polarizations with head-to-tail configuration across the heterointerface. Such discontinuous, downward polarizations support the accumulation of oxygen vacancies at the heterointerface that facilitate the local polarization enhancement. It is the combination effect of stable ferroelectric polarization in the PLZT(T) layer, interfacial oxygen vacancies and large surface to volume ratio that leads to the superior polarization performance of the antiferroelectric sandwich structure. It indicates that interface engineering is a feasible approach to manipulate the ferroic behavior.     

Thickness Dependence of Dielectric,Leakage, and Ferroelectric Properties of Bi6Fe2Ti3O18 Thin Films Derived by Chemical Solution Deposition

We prepared Bi₆Fe₂Ti₃O₁₈ thin films on Pt/Ti/SiO₂/Si substrates with thickness ranging from ～300 to ～900 nm by using a chemical solution deposition route and investigated the thickness effects on the microstructure, dielectric, leakage, and ferroelectric properties of Bi₆Fe₂Ti₃O₁₈ thin films. Increasing thickness improves the surface morphology, dielectric, and leakage properties of Bi₆Fe₂Ti₃O₁₈ thin films and a well‐defined ferroelectric hysteresis loops can form for the thin films with the thickness above 400 nm. Moreover, the thickness dependence of saturation polarization is insignificant, whereas the remnant polarization decreases slightly with increasing thickness and it possesses a maximal value of ～20 μC/cm² for the 500 nm‐thick thin films. The mechanisms of the thickness dependence of microstructure, dielectric, and ferroelectric properties are discussed in detail. The results will provide a guidance to optimize the ferroelectric properties in Bi₆Fe₂Ti₃O₁₈ thin films by chemical solution deposition, which is important to further explore single‐phase multiferroics in the n = 5 Aurivillius thin films.     

Effects of the film thickness and poling electric field on photovoltaic performances of (Pb,La)(Zr,Ti)O3 ferroelectric thin film-based devices

The ferroelectric photovoltaic (FPV) effect obtained in inorganic perovskite ferroelectric materials has received much attention because of its large potential in preparing FPV devices with superior stability, high open-circuit voltage (V_oc) and large short-circuit current density (J_sc). In order to obtain suitable thickness for the ferroelectric thin film as light absorption layer, in which, the sunlight can be fully absorbed and the photo-generated electrons and holes are recombined as few as possible, we prepare Pb_0.93La_0.07(Zr_0.6Ti_0.4)_0.9825O₃ (PLZT) ferroelectric thin films with different layer numbers by the sol-gel method and based on these thin films, obtain FPV devices with FTO/PLZT/Au structure. By measuring photovoltaic properties, it is found that the device with 4 layer-PLZT thin film (~300 nm thickness) exhibits the largest V_oc and J_sc and the photovoltaic effect obviously depends on the value and direction of the poling electric field. When the device is applied a negative poling electric field, both the V_oc and J_sc are significantly higher than those of the device applied the positive poling electric field, due to the depolarization field resulting from the remnant polarization in the same direction with the built-in electric field induced by the Schottky barrier, and the higher the negative poling electric field, the larger the V_oc and J_sc. At a -333 kV/cm poling electric field, the FPV device exhibits the most superior photovoltaic properties with a V_oc of as high as 0.73 V and J_sc of as large as 2.11 μA/cm². This work opens a new way for developing ferroelectric photovoltaic devices with good properties.     

Effect of Si doping on the photocatalytic activity and photoelectrochemical property of TiO2 nanoparticles

Si-doped TiO₂ nanoparticles with anatase crystalline phase were prepared by a hydrothermal method using acetic acid as the solvent. Photoelectrochemical studies showed that the photocurrent value for the 15% Si-doped TiO₂ electrode (54.4 μA) was much higher than that of the pure TiO₂ electrode (16.7 μA). In addition, the 15% Si-doped TiO₂ nanoparticles displayed the highest photocatalytic activity under ultraviolet light irradiation. So doping suitable amount of Si in TiO₂ nanoparticles was profitable for transferring photogenerated electrons and inhibiting the recombination of photogenerated electrons and holes. As a result, the photocatalytic activity of TiO₂ nanoparticles was improved.     

WSe2/2D electron gas heterojunction on KTaO3 for room-temperature giant photoconductivity

Van der Waals (vdW) heterojunctions, based on 2D systems, show great potential as high-performance photodetectors. Recent advances have reported an Ar⁺-ion-bombardment assistant method to achieve a vdW heterojunction between a 2D-material and a 2D electron gas (2DEG). Here, we fabricate a vdW heterojunction between WSe₂ and 2DEG on KTaO₃. Under visible light illumination, a giant photoconductivity is observed with bias voltage applied at room temperature. Such a device exhibits an instantaneous photoelectric response to on/off light illumination. The ratio of on/off currents reaches as high as 10⁴. In the wavelength range of 405–808 nm, the photoresponsivity is much greater for shorter wavelengths, reaching a maximum of 1.84 A/W. Moreover, even without bias voltage, the WSe₂/2DEG heterojunction still generates a short-circuit photocurrent due to the photovoltaic effect, implying a self-powered photodetector. This work paves a path towards high-performance photoelectric devices based on vdW heterojunctions of 2D-material/2DEG.     

Realization of a self-powered ZnSnO MSM UV photodetector that uses surface state controlled photovoltaic effect

Self-powered ultraviolet (UV) photodetectors (PDs) that use a vertical p-n junction generally involve a complex fabrication process if they are to be integrated with optoelectronic integrated circuits (OEICs). This study demonstrates the fabrication of a self-powered metal-semiconductor-metal (MSM) UV PD with simple planar structure using nontoxic and earth abundant ZnSnO (ZTO). The self-powering characteristic is realized using a localized UV-assisted thermal annealing (LUV-TA) process that selectively modifies the surface states underneath different contacts and creates asymmetric Schottky barrier heights (SBHs) for the MSM PD. The a-ZTO MSM PD with assymmetric SBHs operates at a zero bias and has a responsivity of 18.2 mA/W at 350 nm. The open-circuit voltage is 0.40 V under UV illumination at a wavelength of 365 nm (50 mW/cm²). The device exhibits a fast response speed, with a rise time of 38 ms and a decay time of 180 ms. This study demonstrates that this strategy can be extended to other MSM PDs, particularly those that use an amorphous oxide semiconductor as the active layer.     

LaCoO3 acts as a high-efficiency co-catalyst for enhancing visible-light-driven tetracycline degradation of BiOI

Exploring noble-metal-free co-catalysts highly flexible for separating the photogenerated charge carriers is of prime importance for the visible-light-driven photocatalysis. Herein, three-dimensional flower-like BiOI microspheres were fabricated and applied to support noble-metal-free LaCoO₃ co-catalysts to construct a unique LaCoO₃/BiOI hybrid photocatalyst with a higher ability in charge separation. As expected, the optimum tetracycline degradation rate of LaCoO₃ (4.0 wt%)/BiOI was up to 0.0161 min⁻¹, which was nearly 3.4 fold larger than that of pure BiOI (0.0048 min⁻¹). The enhanced photocatalytic performance was mainly ascribed to the vital role of LaCoO₃ co-catalyst, which acted as an excellent electron collector for capturing the electrons generated by BiOI, effectively promoting the separation of photogenerated charge carriers and prolonging the lifetime of photo-induced electron-hole pairs at the same time. Furthermore, the active species trapping experiments revealed that the excellent photocatalytic activity was primarily driven by photogenerated holes and superoxide radicals. This work is expected to provide a new inspiration for rationally designing and fabricating noble-metal-free co-catalyst system with high efficiency applied in environment purification.     

Non-stoichiometric BZT-BCT ferroelectrics with visible/near-infrared photoresponse for broadband photodetection

The bulk photovoltaic effect in ferroelectric materials exhibits great potential in photoelectric applications. However, their photoresponse is generally limited to the UV region due to the wide bandgap feature of most perovskite ferroelectric materials, while the narrowing of bandgap is often accompanied by the degradation or even extinction of the ferroelectric polarization. Herein, 0.5Ba(Zr_0.2Ti_0.8)O₃-0.5(Ba_0.7Ca_0.3)TiO₃ (BZT-BCT) with bandgap of 2.4 eV arising from the existence of Ti³⁺ is prepared, and then titanium vacancies are introduced to BZT-BCT ferroelectric solid solutions through B-site off-stoichiometry (0.5Ba(Zr_0.2Ti_0.8)O₃-0.5(Ba_0.7Ca_0.3)Ti_{1 − x%}O₃, BZT-BCT_{1 − x%}) to further tune the bandgap. Lowest bandgap of 2.1 eV with near-infrared (NIR) absorption is obtained for BZT-BCT_0.990 composition. Moreover, both the ferroelectricity and piezoelectricity (P_r = 14.3 μC/cm², d₃₃ = 415 pC/N) are well maintained after mitigating the effect of the increased oxygen vacancies associated with Ti-deficiency on the spontaneous polarization by oxygen-annealing treatment. More specifically, the oxygen-annealing BZT-BCT_0.985 composition, showing at least 2.4-fold photovoltage and 2.2-fold photocurrent of the pristine BZT-BCT ceramic, exhibits excellent transient pyroelectric current and stable photovoltaic current under xenon, NIR, and monochromatic visible lights. The photoelectric device based on the oxygen-annealing BZT-BCT_0.985 ceramic performs wide-spectrum photodetection properties from 405 nm light to NIR light, which makes it a potential candidate for self-powered photodetector applications.