Realization of Moisture-Resistive Perovskite Films for Highly Efficient Solar Cells Using Molecule Incorporation

Abstract

The development of high-crystalline perovskite films with large crystal grains and few surfacedefects is attractive to obtain high performance perovskite solar cells (PSCs) with good device stability. Herein, we simultaneously improve the power conversion efficiency (PCE) and humid stability of the CH 3 NH 3 PbI 3 (CH 3 NH 3 =MA) device by incorporating small organic molecule IT-4F to the perovskite film and using buffer layer of PFN-Br. The presence of IT-4F in the perovskite film can successfully improve crystallinity and enhance grain size, leading to reduced trap states, longer lifetime of charge carrier and make perovskite film hydrophobic. Meanwhile, as a buffer layer, PFN-Br can accelerate the separation of exciton and promote the collection process of electrons from active layer to cathode. As a consequence, the PSCs present a remarkably improved PCE to 20.55% with reduced device hysteresis. Moreover, the moisture resistive film based devices retain about 80% of its initial efficiency after 30 days of storage in relative humidity (RH) of 10-30% without encapsulation.

Recent Progress on the Stability of Perovskite Solar Cells in a Humid Environment

“…Amazingly, even under extreme conditions (a drop of water was dripped onto the perovskite films coated with ETL), PCBB–S-N/PCBM-coated perovskite film shows strong moisture resistance, which can survive more than 240 s. In stark contrast, the color of the PCBM-coated perovskite films immediately changed from black to yellow. Moreover, studies have shown that adding IT-4F to the perovskite film can improve crystallinity and increase the grain size, thereby reducing trap states, extending the charge carrier lifetime, and making the perovskite film hydrophobic . After storage for 30 d in an environment with 10–30% relative humidity, the unencapsulated device based on the IT-4F modified perovskite film retains ∼80% of the initial PCE (20.55%).…”

“…Moreover, studies have shown that adding IT-4F to the perovskite film can improve crystallinity and increase the grain size, thereby reducing trap states, extending the charge carrier lifetime, and making the perovskite film hydrophobic. 122 After storage for 30 d in an environment with 10−30% relative humidity, the unencapsulated device based on the IT-4F modified perovskite film retains ∼80% of the initial PCE (20.55%). 3.4.…”

Significantly Enhanced Visible‐Light H2 Evolution of Polyfluorene Polyelectrolyte by Anionic Polyelectrolyte Doping

“…Cationic poly[9,9dioctyl-9′,9′-bis[3-(ethyl(dimethyl)ammonio)propyl][2,2′-bi-9Hfluorene]-7,7′-diyl bromide, namely PFN-Br, was chosen as the energy donor due to its strong light harvesting ability, excellent photoelectric properties and promising photocatalytic activity. [27,28] However, PFN-Br shown strong fluorescence in CH 3 OH with photoluminescence quantum yield (PLQY) up to 0.53 (coumarin 153 in ethanol as the fluorescence reference). Clearly, this large energy loss though fluorescence irradiation is not beneficial to photochemical conversion.…”

Low Dark Current and Performance Enhanced Perovskite Photodetector by Graphene Oxide as an Interfacial Layer

“…Numerous efforts have been made to overcome these obstacles, for instance, by incorporating small molecules [26], using an efficient electron transport layer [27], blending of acceptor and donor materials [28], and integrating conventional semiconductors such as metal oxides and functional 2D materials [14,19]. For instance, Chen et al proposed the multilayer structure of organic/inorganic materials for attaining high responsivity in hybrid photodetectors [29].…”