Strategy to overcome recombination limited photocurrent generation in CsPbX3 nanocrystal arrays

Abstract

We discuss the transport properties of CsPbBrxI3−x perovskite nanocrystal arrays as a model ensemble system of caesium lead halide-based perovskite nanocrystal arrays. While this material is very promising for the design of light emitting diodes, laser, and solar cells, very little work has been devoted to the basic understanding of their (photo)conductive properties in an ensemble system. By combining DC and time-resolved photocurrent measurements, we demonstrate fast photodetection with time response below 2 ns. The photocurrent generation in perovskite nanocrystal-based arrays is limited by fast bimolecular recombination of the material, which limits the lifetime of the photogenerated electron-hole pairs. We propose to use nanotrench electrodes as a strategy to ensure that the device size fits within the obtained diffusion length of the material in order to boost the transport efficiency and thus observe an enhancement of the photoresponse by a factor of 1000.

Revealing the Band Structure of FAPI Quantum Dot Film and Its Interfaces with Electron and Hole Transport Layer Using Time Resolved Photoemission

“…Note that it is very close to the value found for CsPbI3 which is 4.1 ± 0.05 eV. 9,32 The vicinity of these two values relates to the fact that in lead halide perovskite material, the states close to the Fermi level mostly result from lead orbitals, which give rise to similar values between these two compounds. 33 The analysis of the valence band is generally used to determine the exact position of the Fermi level within the band gap.…”

Impact of dimensionality and confinement on the electronic properties of mercury chalcogenide nanocrystals

“…At early time scale, there is a fast decay corresponding to carrier recombination, this decay time generally matches well with the PL decay time. 39 In the case of HgTe CQDs, we observe a fast decay of 0.5 ns, see Figure 5b. This measurement is actually limited by the pulse length which is consistent with previously reported PL decay 40 measured on similar size of HgTe CQDs for which a bi-exponential behavior was observed with decay time of 50 ps and 2 ns.…”

Photovoltaic and photocatalytic properties of bismuth oxyiodide–graphene nanocomposites

“…Photocurrent generation is limited by electron-hole recombination and photocurrent response is related to the lifetime of complete charge separated state. 39,40 The graphene in BiOI-GR thin lm served as electron acceptor, hence photogenerated charge carrier recombination is prevented and the carrier life time of the charges were extended, hence generating higher photocurrent. This is illustrated in Fig.…”