Causes and Solutions of Recombination in Perovskite Solar Cells

Abstract

Organic-inorganic hybrid perovskite materials are receiving increasing attention and becoming star materials on account of their unique and intriguing optical and electrical properties, such as high molar extinction coefficient, wide absorption spectrum, low excitonic binding energy, ambipolar carrier transport property, long carrier diffusion length, and high defects tolerance. Although a high power conversion efficiency (PCE) of up to 22.7% is certified for perovskite solar cells (PSCs), it is still far from the theoretical Shockley-Queisser limit efficiency (30.5%). Obviously, trap-assisted nonradiative (also called Shockley-Read-Hall, SRH) recombination in perovskite films and interface recombination should be mainly responsible for the above efficiency distance. Here, recent research advancements in suppressing bulk SRH recombination and interface recombination are systematically investigated. For reducing SRH recombination in the films, engineering perovskite composition, additives, dimensionality, grain orientation, nonstoichiometric approach, precursor solution, and post-treatment are explored. The focus herein is on the recombination at perovskite/electron-transporting material and perovskite/hole-transporting material interfaces in normal or inverted PSCs. Strategies for suppressing bulk and interface recombination are described. Additionally, the effect of trap-assisted nonradiative recombination on hysteresis and stability of PSCs is discussed. Finally, possible solutions and reasonable prospects for suppressing recombination losses are presented.

Chlorine‐modified SnO2 electron transport layer for high‐efficiency perovskite solar cells

“…Thus far, the certified efficiency of cells with a SnO 2 ETL has reached 23.3%, the highest efficiency for the planar‐type PSCs reported to date; however, based on the Shockley‐Queisser theory, the theoretical PCE limit is 30.5%. The main reason for PCE loss is carrier recombination . In SnO 2 ‐planar PSCs, the SnO 2 /perovskite interface is very important to attain high efficiency and stable PSCs, considering the necessity of minimizing interface nonradiative recombination losses, which result from interfacial defects or imperfect energy band alignment.…”

“…The main reason for PCE loss is carrier recombination. 38 In SnO 2 -planar PSCs, the SnO 2 /perovskite interface is very important to attain high efficiency and stable PSCs, considering the necessity of minimizing interface nonradiative recombination losses, which result from interfacial defects or imperfect energy band alignment. Great progress has been made on optimizing and modifying the SnO 2 /perovskite interface over the past few years, 15,[39][40][41][42][43][44] For instance, Wang et al prepared a full-coverage SnO 2 ETL by modulating the water absorbed on the substrate at~50 C, and high PCEs of 20.5 and 17.5% were obtained on rigid and flexible PSC devices, respectively.…”

Fully Air‐Processed Carbon‐Based Efficient Hole Conductor Free Planar Heterojunction Perovskite Solar Cells With High Reproducibility and Stability

“…ESL quality is crucial for high performance devices, since it is responsible for charge collection and transportation in devices as well as blocking holes from recombination. [49,50] As we can see from the top-view and cross-sectional SEM images ( Figure 2 and Figure S1, Supporting Information), 40 nm c-TiO 2 ESL is very thin, and it shows the intrinsic feature of FTO with numerous exposed islands on the surface of ESL. This will cause serious recombination at the interface of TiO 2 /CH 3 NH 3 PbI 3 due to the poor electron selection and hole blocking properties.…”

“…The detailed photovoltaic parameters of these devices are summarized in Table . ESL quality is crucial for high performance devices, since it is responsible for charge collection and transportation in devices as well as blocking holes from recombination . As we can see from the top‐view and cross‐sectional SEM images (Figure and Figure S1, Supporting Information), 40 nm c‐TiO 2 ESL is very thin, and it shows the intrinsic feature of FTO with numerous exposed islands on the surface of ESL.…”

Anorganische CsPbX3‐Perowskit‐Solarzellen: Fortschritte und Perspektiven

“…Außer dass Perowskite mit hohem E g (hauptsächlich die reinen Bromide oder Br-reichen Verbindungen) bisher einen hçheren Spannungsverlust aufweisen als die Iodide (der Spannungsverlust wird in Abschnitt 4.4.4 behandelt [48] Fürd ie Diffusionslängen und die damit verbundenen Parameter (Ladungsträgermobilitäten und -lebensdauern) von CsPbX 3 gibt es noch immer nur wenige Daten. B. den III-V-Halbleitern), über den gesamten sichtbaren und Nah-IR-Bereich abgestimmt werden.…”