Cs4CuSb2Cl12−xIx (x = 0–10) nanocrystals for visible light photodetection. (8th October 2022)

• Record Type: Journal Article
• Authors: Mandal, Arnab; Mondal, Anamika; Bhattacharyya, Rachana; Bhattacharyya, Sayan
• Is Part Of: Nanotechnology. Volume 33:Number 41(2022)
• Publication Date: 2022-10-08
• Subjects: layered double perovskite -- nanocrystal -- exciton binding energy -- photoluminescence -- photodetector; Nanotechnology -- Periodicals; Nanotechnology -- Periodicals; Nanotechnology; Publications périodiques; Nanotechnologies; Periodicals; 620.5
• DOI: 10.1088/1361-6528/ac7ed2
• Languages: English
• ISSNs: 0957-4484

Abstract

Abstract: Lead-free layered double perovskite nanocrystals (NCs) with tunable visible range emission, high carrier mobility and low trap density are the need of the hour to make them applicable for optoelectronic and photovoltaic devices. Introduction of Cu 2+ in the high band gap Cs3 Sb2 Cl9 lattice transforms it to the monoclinic Cs4 CuSb2 Cl12 (CCSC) NCs having a direct band gap of 1.96 eV. The replacement of 50% Cl − by I − ions generates <5 nm Cs4 CuSb2 Cl6 I6 (C6I6) monodispersed NCs with an unchanged crystal system but with further lowering of the band gap to 1.92 eV. The p -type C6I6 NCs exhibit emission spectra, lower trap density, appreciable hole mobility and most importantly a lower exciton binding energy of only 50.8 ± 1.3 meV. The temperature dependent photoluminescence (PL) spectra of the C6I6 NCs show a decrease in non-radiative recombination from 300 K down to 78 K. When applied as the photoactive layer in out-of-plane photodetector devices, C6I6 NC devices exhibit an appreciable responsivity of 0.67 A W −1 at 5 V, detectivity of 4.55 × 10 8 Jones (2.5 V), and fast photoresponse with rise and fall time of 126 and 94 ms, respectively. On the other hand, higher I - substitution in Cs4 CuSb2 Cl2 I10 NCs (C2I10) degrades the lattice into a mixture of monoclinic and trigonal crystal phases, which also lowers the device performance.