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Weak light detection is a current research topic and chlorine-containing lead-free perovskite materials are promising. In this research work, Cl-incorporated methylammonium Sb mixed halide perovskite (CH3NH3)3 (Sb)2(Cl)X I(9−X) derivatives were investigated for weak light detection. We have devised a solution-processable slow crystal growth (SCG) to fabricate 2D layered (CH3NH3)3 (Sb)2(Cl)X I(9−X) lead-free perovskite microcrystals. SCG facilitate only 1.51 atomic percent chlorine incorporation confirmed in FESEM-EDS analysis and band gap 1.98 eV determines the SCG grown lead-free perovskite molecular formula to be (CH3NH3)3 (Sb)2(Cl)X I(9−X). FTO/ (CH3NH3)3 (Sb)2(Cl)X I(9−X) PMCs/FTO self-powered photodetector detect 400 nm, 1µW cm−2 weak optical signal. (CH3NH3)3 (Sb)2(Cl)X I(9−X) respond to weak optical signals in the 300–600 nm wavelength range. Also, (CH3NH3)3 (Sb)2(Cl)X I(9−X) exhibit a high reflectance (> 70%) for the wavelength above 600 nm with its inherent thermodynamic stability is a candidate for use as a reflective layer in tandem solar cells. [ABSTRACT FROM AUTHOR]

Abstract: We discuss a technique and a material system that enable the controlled realization of quantum entanglement between spin-wave modes of electron ensembles in two spatially separated pieces of semiconductor material. The approach uses electron ensembles in GaAs quantum wells that are located inside optical waveguides. Bringing the electron ensembles in a quantum Hall state gives selection rules for optical transitions across the gap that can selectively address the two electron spin states. Long-lived superpositions of these electron spin states can then be controlled with a pair of optical fields that form a resonant Raman system. Entangled states of spin-wave modes are prepared by applying quantum-optical measurement techniques to optical signal pulses that result from Raman transitions in the electron ensembles. [Copyright &y& Elsevier]