Charge transport properties and variable photo-switching of three-terminal Cs_(2)AgBiBr_(6) device

In this study,we present an in-depth exploration of charge transport phenomena and variable photo-switching characteristics in a novel double-perovskite-based three-terminal device.The Cs_(2)AgBiBr_(6) thin film(TF)was synthesized through a three-step thermal evaporation process followed by precise open-air annealing,ensuring superior film quality as confirmed by structural and morphological characterizations.Photoluminescence spectroscopy revealed distinct emissions at 2.28 and 2.07 eV,indicative of both direct and indirect electronic transitions.Our device exhibited space-charge limited current(SCLC)behaviour beyond 0.35 V,aligning with the relationship Current(I)∝Voltage(V)^(m),where the exponent m transitioned from≤1 to>1.Detailed analysis of Schottky parameters within the trap-filled limit(TFL)regime was conducted,accounting for variations in temperature and optical power.Significantly,the self-powered photodetector demonstrated outstanding performance under illumination.The sensitivity of the device was finely tunable via the applied bias voltages at the third terminal.Notably,an optimal bias voltage of±100μV yielded maximum responsivity(R)of 0.48 A/W and an impressive detectivity(D*)of 1.07×10^(9) Jones,highlighting the potential of this double-perovskite-based device for advanced optoelectronic applications.

CuO–TiO_(2) based self-powered broad band photodetector

An efficient room-temperature self-powered,broadband(300 nm–1100 nm)photodetector based on a CuO–TiO_(2)/TiO_(2)/p-Si(100)heterostructure is demonstrated.The CuO–TiO_(2)nanocomposites were grown in a two-zone horizontal tube furnace on a 40 nm TiO_(2)thin film deposited on a p-type Si(100)substrate.The CuO–TiO_(2)/TiO_(2)/p-Si(100)devices exhibited excellent rectification characteristics under dark and individual photoillumination conditions.The devices showed remarkable photo-response under broadband(300–1100 nm)light illumination at zero bias voltage,indicating the achievement of highly sensitive self-powered photodetectors at visible and near-infrared light illuminations.The maximum response of the devices is observed at 300 nm for an illumination power of 10 W.The response and recovery times were calculated as 86 ms and 78 ms,respectively.Moreover,under a small bias,the devices showed a prompt binary response by altering the current from positive to negative under illumination conditions.The main reason behind this binary response is the low turn-on voltage and photovoltaic characteristics of the devices.Under illumination conditions,the generation of photocurrent is due to the separation of photogenerated electron-hole pairs within the built-in electric field at the CuO–TiO_(2)/TiO_(2)interface.These characteristics make the CuO–TiO_(2)/TiO_(2)broadband photodetectors suitable for applications that require high response speeds and self-sufficient functionality.

Synthesis of Nanocrystalline FeS_2 with Increased Band Gap for Solar Energy Harvesting

In this paper,we have reported the synthesis of FeS2 of higher band gap energy（2.75 eV） by using capping reagent and its successive application in organic-inorganic based hybrid solar cells.Hydrothermal route was adopted for preparing iron pyrite（FeS2） nanoparticles with capping reagent PEG-400.The quality of synthesized FeS2 material was confirmed by X-ray diffraction,field emission scanning electron microscopy,transmission electron microscopy,Fourier transform infrared,thermogravimetric analyzer,and Raman study.The optical band gap energy and electro-chemical band gap energy of the synthesized FeS2 were investigated by UV-vis spectrophotometry and cyclic voltammetry.Finally band gap engineered FeS2 has been successfully used in conjunction with conjugated polymer MEHPPV for harvesting solar energy.The energy conversion efficiency was obtained as 0.064%with a fill-factor of 0.52.