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The perovskite single crystals (PSC) produced by solution‐processed metallic ions doping have a thick p–n junction (greater than 10 µm). Meanwhile, to achieve high responsivity, the carrier drift length (µτE) has to be larger than the dimensions of the detector. If the p–n junction is quite thick, a high bias voltage is required. For the practical application of photodiode, it is imperative to find a means to generate a thin p–n junction. A productive technique is suggested for forming a thin p–n junction by diffusing metallic ions, resulting in a longer drift length of the carrier than the depletion width. Thinner p–n junction leads to reduced dark current density (0.5 µA cm−2), low trap density (5.71 × 108 cm−3), high mobility (417 cm2 V−1 s−1), and hence increased responsivity (77.69 A W−1) for 30 µW cm−2 UV illumination under a low applied voltage of −15 V. A quick response time with a rise/fall duration of 22 ms/30 ms under 0 V and long‐term stability for over 3 months in ambient airis achieved. To comprehend the performance with the thinner p–n junction‐based photodiodes, the results under UV–Vis illumination are examined and compared. The outcomes hint at a method that holds promise for producing efficient photodiodes. [ABSTRACT FROM AUTHOR]

Low‐cost and efficient large‐scale triboelectric nanogenerator (TENG) is considered as the new scheme for distributed mechanical conversion or renewable energy utilization. An extremely popular all‐inorganic lead‐free double perovskite Cs2AgBiBr6 (CABB) has emerged as extraordinary potential material in triboelectric semiconductors' substitution, overcoming high‐impedance limitations associated with organic‐polymer‐insulator based materials. In this study, assembled by the certified available positive frictional material CABB, TENG with sandwiched structure of ITO/compact‐TiO2/mesoporous‐TiO2/CABB – the poly‐tetra‐fluoroethylene/Al exhibits appropriate performance on environmental stability and output capacity for which structure can impede charges decay. Fabrication process comparison shows that as an inexpensive large‐scale functional films preparation method, sprayed CABB TENG with brilliant relative dielectric constant and work function difference possess more distinguished output characteristics. This is confirmed by higher open‐circuit voltage of 105 V, larger short‐current density of 2.45 mA m−2 at 0.25 Hz motion parameter, and more abundant output power density of 0.76 W m−2 under 10 Hz. Further study confirms that both higher frequency and larger contact‐area are conducive to total output power, while terminal charging speed is inversely or positively proportional with capacitance or mechanical frequency. Final physical display effect of sprayed CABB TENG lights up at least 53 commercial yellow‐LEDs, holding decent energy conversion ability. [ABSTRACT FROM AUTHOR]

Compared with the pure lead-based MAPbBr3 (MA = CH3NH3) perovskite single crystals (PSCs), tin–lead alloy (MAPbxSn1−xBr3) PSCs with higher carrier mobility and longer carrier lifetime are expected to perform as better-quality ionization radiation detectors. In this work, we design MAPbBr3–MAPb0.9Sn0.1Br3–MAPb0.8Sn0.2Br3 structure detectors by employing solution-process epitaxial growth. Because of the gradient change in tin element proportion, the relatively low mismatch rates between different PSC layers can effectively reduce defects generated at the interface, which improves charge collection efficiency. Moreover, band barriers between different PSC layers form depletion layers due to the differences in band structure, and the high resistivity and built-in electric field of depletion layers can suppress dark current under high voltages. The optimized detector exhibits a high x-ray detection sensitivity of 6.76 × 104μC Gy−1 cm−2 and the lowest detectable dose rate of 7.4 nGy s−1 under 40 kVp x-ray radiation. Based on 241Am (5.95 MeV) α particle irradiation, tin–lead HD has lower detection noise and more obvious response compared to MAPbBr3 PSCs. The electron mobility was indicated as high as 612 cm2 s−1 V−1, and the mobility-lifetime (μτ) products were measured to be 3.5 × 10−3 cm2 V−1 using the Hecht equation, demonstrating superior transport properties. [ABSTRACT FROM AUTHOR]

Narrowband photodetection provides important information in a specific wavelength range. Specially, the use of nonoptical‐filter narrowband photodetectors based on MAPbX3 (MA = CH3NH3; X = Cl, Br, I) perovskites is reported of great potential. However, current MAPbX3‐based narrowband photodetectors have to sacrifice their photocurrent and response speed to achieve an acceptable spectral rejection ratio. In this work, a new type of heterojunction photodetector (hetero‐PD) with a structure of (n‐type doped MAPbCl3)/(intrinsic MAPbBr2.5Cl0.5)/(n‐type doped MAPbBr3) via epitaxial growth is demonstrated as a narrowband photodetector. Through optical bandgap engineering, photons with different wavelength can be absorbed in different layers. Owing to the n–i–n energy band structure, most external bias would apply on a tiny region near the n–i heterojunction. Besides, the energy barriers in the heterojunctions can block holes from injection and collection, resulting in low‐noise electron‐only hetero‐PDs. By sufficiently suppressing the background noise from short‐wavelength photons, hetero‐PDs are capable of achieving a high spectral rejection ratio of 98.1% under an electrical field of 8 V cm−1. Moreover, hetero‐PDs exhibit a high external quantum efficiency value of 45%, a narrow full width at half‐maximum of 13 nm, and a response time of 1.35 µs. [ABSTRACT FROM AUTHOR]

All-inorganic halide semiconductors with perovskite or perovskite-like structure have aroused a widespread concern recently for its environmental friendliness and stabilities while possessing excellent optoelectronic properties. Double perovskite Cs2AgBiBr6 single crystal (SC) is one of the most representative materials in the latest research area. To further improve the device response range and decrease its dark current density effectively, functional layers based on the solution-processed epitaxial method are normally fabricated as heterojunctions. Herein, a novel idea of a broadband heterojunction MAPbI3 (MA = CH3NH3)/Cs2AgBiBr6 is proposed in this work to achieve this goal. A MAPbI3 layer is fabricated on Cs2AgBiBr6 SC substrates through immersing Cs2AgBiBr6 SC into MAPbI3 solution at a MAPbI3 crystallization temperature. Ultimately, this heterojunction device expands the absorption limit from 618 to 838 nm, makes responsivity range redshift from 629 to 860 nm, and achieves a responsivity of 16.8 mA W−1 while the detectivity of 1.33 × 1011 Jones under 622 nm 0.55 mW cm−2 illumination at −20 V bias, maintaining excellent optoelectronic properties. [ABSTRACT FROM AUTHOR]

The ion migrations in lead halide perovskite (LHP)‐based devices are complex processes due to the generation of charges and migration multipaths. The migrating ions are generated mainly from element defects and dislocation defects, and transport along paths of element vacancies and grain boundaries. In this regard, it is of interest to investigate the different influences of the two defect types and paths. Herein, the current–voltage hysteresis and X‐ray photoelectron spectra of almost‐dislocation‐free LHP single crystals (LHPSCs) with different halide components are investigated. The ions cannot migrate in iodine‐based LHPSCs. A decrease in halide vacancy content in a bromine–chlorine‐based perovskite single crystal can effectively limit the ion migration. This study provides useful insights to understand the different dominant factors determining the ion migration in LHPs. [ABSTRACT FROM AUTHOR]

We have utilized CsPbBr 3 +PEO+PVP (Pero+polymer) composite film for efficient UV-photodetection. The polymers improve the surface coverage, surface passivation, UV-light absorption, stability, charge carrier lifetime, where the good ionic conduction of PEO, improves the carrier transportation in the Pero-polymer composite film to enhance detection. This composite film works well for 450 nm-550 nm photodetection and is excellent for UV-photodetection as compared to conventional perovskite film. [Display omitted] • The polymers in the composite film improved the surface coverage, surface passivation, light absorption, stability, charge carrier life time. • The addition of PVP polymer enhanced the photocurrent and addition of PEO reduced the dark current. • The optimized CsPbBr 3 -polymer based PD has achieved a high photo-to-dark current ratio, responsivity and specific detectivity 106, 55.3 AW−1 and 5.67 × 1013 Jones, All inorganic cesium lead bromide (CsPbBr 3) perovskite is being extensively applied to optoelectronics due to its facile solution processability and extraordinary optical properties. However, the expansion of its implementation in optoelectronic devices is being hindered due to the poor surface coverage of its film, inefficient charge transportation, long-term instability, and requirements of complex fabrication techniques. Here, a facile solution-processed composite perovskite film composed of CsPbBr 3 polycrystals merged with polymers such as polyethylene oxide (PEO) and polyvinylpyrrolidone (PVP) has been introduced to act as a light absorber for efficient ultraviolet (UV) light detection. The as-used polymers in the composite film have improved the surface coverage, surface passivation, light absorption, stability, charge carrier lifetime due to the high UV-Absorption tendency of CsPbBr 3 and transport capability strengthened by the good ionic conduction of PEO, which results in an efficient UV-photodetection. Compared to the pristine CsPbBr 3 film-based PD, the CsPbBr 3 -polymer based PD has achieved a high photo-to-dark current ratio, responsivity and specific detectivity of up to 106, 55.71 AW−1 and 8.07 × 1013 Jones, respectively, at a very low bias voltage of 0.2 V using 365 nm light source. The device has shown excellent stability of over 3 weeks under ambient environmental conditions. [ABSTRACT FROM AUTHOR]

• The double cation halide perovskite MACsPbBr 3 embedded in polymers constitute the film with improved surface coverage, surface passivation, light absorption, stability, and charge carrier lifetime. • The introduction of AuNPs enhances the light absorption and extraction efficiency of carriers to further enhance the device performance. • The incorporation of MAPbBr 3 -Pero+PVDF in CsPbBr 3 -Pero increased surface coverage with and a large number of smooth crystals surrounded by MA-Pero+PVDF crystal, which decreased surface roughness to provide better interfacial contact with the top electrode. • The addition of PVDF polymer reduced dark current the photocurrent and the addition of PVP improved uniform dispersivity as compared to PEO and improved photocurrent. • The optimized plasmonic enhanced MACsPbBr 3 -polymer-based PD has achieved a high photo-to-dark current ratio, responsivity, and specific detectivity >106, 55.91 AW−1, and 7.91×1014 Jones, which is 1.12-fold and 10-folds greater than that for the no-plasmonic device. Organic-inorganic hybrid perovskite is being extensively applied to optoelectronics. However, the complex fabrication techniques, long-term instability, inefficient charge transportation; poor surface coverage hinders the expansion of its applications. Herein, we report for the first time the in-situ synthesis of MACsPbBr 3 -perovskite crystals in polymer-matrix to act as a light absorber for efficient ultraviolet light detection. The devices fabricated with the MACsPbBr 3 -perovskite films showed a maximum photocurrent of 8.9 × 10−6, a dark current of 1.7 × 10−11 A, responsivity of 45.75 AW−1, detectivity of 1.05 × 1013 Jones and on/off ratio >105 at 0 V, under the illumination of 0.28 mW cm−2. The plasmonic enhancement was explored by fabricating PDs on (gold nanoparticles) AuNPs/ZnO structure, which exhibited photocurrent enhancement (10−5), ascribed to the huge localized electric field induced by the surface plasmon resonance, scattering, and reflectance from AuNPs and structured ZnO surface, and improved the responsivity (55.91 AW−1) and on/off ration (>106) by 1.12-fold and 10-fold. And the formed Schottky barrier between Pero and AuNPs/ZnO region could lead to the reduced dark current (10−13 A) and improved detectivity (7.91 × 1014 Jones). This study offers a different pathway for the designing of high-performance plasmonic PDs. We have utilized MACsPbBr 3 +PVDF+PVP (Pero+Polymer) composite film for efficient UV-photo detection. Also, we have employed the same composite film to investigate plasmonic enhanced photodetector. The addition of MA-Pero in the PVDF matrix not only improves the surface coverage but also reduces the dark current due to PVDF. MA-Pero+PVDF combined with Cs-Pero+PVP overall improves surface coverage, surface passivation, UV-light absorption, stability, and charge carrier lifetime. Preparing this composite film on the structured layer of AuNPs/ZnO improves not only absorption but the carrier transportation in the Pero-polymer composite film to enhance the detection and response of photodetector due to the additional effect of scatterings, reflectance, and electric field enhancement. Such photodetector provides efficient photodetection at 410 nm as compared to conventional perovskite film. [Display omitted] [ABSTRACT FROM AUTHOR]