High Photoluminescence Quantum Yield in Band Gap Tunable Bromide Containing Mixed Halide Perovskites

Abstract

Hybrid organic-inorganic halide perovskite based semiconductor materials are attractive for use in a wide range of optoelectronic devices because they combine the advantages of suitable optoelectronic attributes and simultaneously low-cost solution processability. Here we present a two-step low pressure vapor-assisted solution process to grow high quality homogeneous CH 3 NH 3 PbI 3-x Br x perovskite films over the full band gap range of 1.6 eV to 2.

Intriguing Optoelectronic Properties of Metal Halide Perovskites

“…44,211 An issue that has come to light recently in mixed-halide MHPs is photoinduced segregation of the solid solution, yielding separate domains that are rich in only one of the constituent halides. 209,212,213 This effect is particularly evident when 0.5 ≤ x < 1 in AB(I 1−x Br x ) 3 compounds. 209 Initial evidence indicates the mixed-cation system protects against this photoinstability, although the mechanism has yet to be identified.…”

“…207,208 In this case, a material's intrinsic propensity for efficient energy conversion can be expressed as qV OC = E g − TΔS − k B T|ln iPLQY|, where S is the entropy and iPLQY is the internal photoluminescence quantum yield. 209,210 Because subgap states act as prominent nonradiative recombination channels, particularly at the relatively low carrier densities in PV operation (section 4.3), the general trend between E u and (E g − qV oc ) is rather intuitive. Despite low-temperature processing, the fact that CH 3 NH 3 PbI 3 and other MHPs have Urbach energies comparable to c-Si (11 meV) and lower than that of CIGS is a testament to their high semiconducting quality and relative resilience to formation of deep electronic defects.…”

Band Tailing and Deep Defect States in CH3NH3Pb(I1–xBrx)3 Perovskites As Revealed by Sub-Bandgap Photocurrent

“…Both time-resolved photoluminescence (PL) 26 and PL quantum yield 15 recombination is the limiting mechanism at low illumination intensities, which are of relevance to the current work. In particular, the former study explained the monoexponential decay observed at low laser fluence by monomolecular (trap-assisted) recombination and the latter study suggested that trap-assisted recombination limits the PL quantum yield at illumination intensities ≤ 1 sun for 0 ≤ x ≤ 1.…”

Influence of Schottky contact on the C-V and J-V characteristics of HTM-free perovskite solar cells

“…However, due to limited Internal PL quantum yield (iQY) and non-zero entropy, the maximum V OC [14] is smaller than E g :…”