Understanding the Impact of Bismuth Heterovalent Doping on the Structural and Photophysical Properties of CH₃NH₃PbBr₃ Halide Perovskite Crystals with Near‐IR Photoluminescence

Abstract

Ac omprehensive study unveiling the impacto f heterovalent doping with Bi 3 + on the structural,s emiconductive, and photoluminescent properties of as ingle crystal of lead halide perovskites (CH 3 NH 3 PbBr 3 )i sp resented.A si ndicatedb ys ingle-crystal XRD, ap erfect cubic structure in Bi 3 + -doped CH 3 NH 3 PbBr 3 crystals is maintainedina ssociation with as light lattice contraction. Time-resolved andp owerdependent photoluminescence( PL) spectroscopy illustrates ap rogressivelyq uenched PL of visible emission, alongside the appearance of an ew PL signal in the near-infrared( NIR) regime,w hich is likely to be due to energy transfer to the Bi sites. These optical characteristics indicatet he role of Bi 3 + dopants as nonradiative recombination centers, which explains the observed transition from bimolecular recombina-tion in pristine CH 3 NH 3 PbBr 3 to ad ominant trap-assisted monomolecular recombination with Bi 3 + doping. Electrically, it is found that the mobility in pristine perovskite crystals can be boosted with al ow Bi 3 + concentration,w hich may be related to atrap-filling mechanism.Aided by temperature (T)-dependentm easurements, two temperature regimes are observed in association with differenta ctivation energies (E a ) for electrical conductivity.T he reduction of E a at lower T may be ascribed to suppression of ionic conduction induced by doping. The modified electrical properties and NIR emission with the control of Bi 3 + concentration shed light on the opportunity to apply heterovalent doping of perovskite single crystals forN IR optoelectronic applications.

Low-noise X-ray PIN photodiodes made of perovskite single crystals by Solution-processed doped epitaxial growth

“…The Urbach energy 41,42 is lower in pristine MAPbBr2.5Cl0.5 and MAPbBr3 MHPSCs than in the Bidoped and Ag-doped layers, which indicates that more traps exist inside the doped layers. The band gap remains at 2.19 eV for the doped MAPbBr3 MHPSC as reported previously 33,43 . Further, the play the role of dopants, as calculated in a previous report 33 .…”

“…The band gap remains at 2.19 eV for the doped MAPbBr3 MHPSC as reported previously 33,43 . Further, the play the role of dopants, as calculated in a previous report 33 . The Ag-doped p-type layer may be formed due to the Ag dopants, leading to a higher excess of Br in the MAPbBr3 MHPSC and making the MHPSC more p-type 37 .…”

“…MHPSCs. Among the 16 types of metal bromide investigated, bismuth bromide [31][32][33][34][35][36] (BiBr3) and silver bromide 37 (AgBr) are considered the most effective donors and acceptors, respectively, due to the high thermally induced diffusion current.…”

Defects and Their Passivation in Hybrid Halide Perovskites toward Solar Cell Applications

“…[116] In addition, at low concentration of doping, Bi 3þ dopants have been found to fill the trap states and improve ionic conductivity of the perovskite; at a higher concentration of doping, they act as nonradiative recombination centers, leading to a transition from bimolecular recombination in pristine MAPbX 3 perovskites to a dominant trap-assisted monomolecular recombination process. [117,118] Abdi-Jalebi et al reported doping of MAPbI 3 with monovalent cations (Na þ , Cu þ , and Ag þ ) having an ionic radius similar to that of bivalent lead cations. Such heterovalent substitution has led to an improvement in the PCE of solar cells based on doped materials.…”

“…[ 116 ] In addition, at low concentration of doping, Bi 3+ dopants have been found to fill the trap states and improve ionic conductivity of the perovskite; at a higher concentration of doping, they act as nonradiative recombination centers, leading to a transition from bimolecular recombination in pristine MAPbX 3 perovskites to a dominant trap‐assisted monomolecular recombination process. [ 117,118 ]…”