Tuning Halide Composition Allows Low Dark Current Perovskite Photodetectors With High Specific Detectivity. Issue 24 (6th October 2022)

• Record Type: Journal Article
• Authors: Furlan, Francesco; Nodari, Davide; Palladino, Emanuele; Angela, Edoardo; Mohan, Lokeshwari; Briscoe, Joe; Fuchter, Matthew J.; Macdonald, Thomas J.; Grancini, Giulia; McLachlan, Martyn A.; Gasparini, Nicola
• Is Part Of: Advanced optical materials. Volume 10:Issue 24(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-06
• Subjects: halide composition -- high specific detectivity -- low dark current -- perovskite photodetectors -- trap states; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.202201816
• Languages: English
• ISSNs: 2195-1071

Abstract

Abstract: Tuning halide composition in perovskites is a powerful approach demonstrated to enhance the performance of perovskite photovoltaic devices where such compositional modifications drive improvements in open‐circuit voltage ( V oc ) and a reduction in nonradiative voltage losses. Similarly, photodetectors (PDs) operate as light to current conversion devices hence it is relevant to investigate whether performance enhancements can be achieved by similar strategies. Herein, perovskite PDs are fabricated with an inverted photodiode configuration based on a MAPb(I1‐ x Br x )3 perovskite (MA = methylammonium) active layer over the x = 0–0.25 composition range. Interestingly, it has been found that increasing the Br content up to 0.15 (15%) leads to a significant reduction in dark current ( J d ), with values as low as 1.3 × 10 −9 A cm −2 being achieved alongside a specific detectivity of 8.7 × 10 12 Jones. Significantly, it has been observed an exponential relationship between the J d of devices and their V oc over the 0–15% Br range. The superior performances of the 15% Br‐containing devices are attributed to the reduction of trap states, a better charge extraction of photogenerated carriers, and an improvement in photoactive layer morphology and crystallinity. Abstract : Here, it has been shown that tuning the iodide–bromide composition into methylammonium lead iodide perovskite photodetectors allows ultra‐low dark current of 1.3 nA cm −2 and high specific detectivity of ≈10 13 Jones with 15% bromide addition. Significantly, an exponential relationship between the dark current of devices and their open circuit voltage over the 0–15% Br range is observed.