Flexible Perovskite Solar Modules with Functional Layers Fully Vacuum Deposited

Abstract

Large‐area homogeneous and uniform perovskite films are key to the mass production of perovskite solar cells, especially the flexible ones. Different from the solution‐processed preparation, herein an all‐evaporation technique is developed for both perovskite films and the hole‐transporting layer in the modules. With the two‐step strategy of active‐layer design, homogeneous large‐area perovskite films are prepared via evaporation of first PbI2 and then CH3NH3I. An 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ)‐doped 4,4′,4″‐tris(N‐(aphthalene‐2‐yl)‐N‐phenylamino)triphenylamine (2T‐NATA) hybrid hole‐transporting layer is deposited on the indium‐tin‐oxide electrode via coevaporation. A power conversion efficiency (PCE) beyond 13% is achieved with the as‐prepared flexible perovskite solar module (active area of 16.0 cm2), which exhibits both higher stability and higher efficiency than the conventional solution‐processed module using poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS) as the hole‐transporting material. This novel strategy of all‐evaporation functional layers provides a feasible way for the industrialization of flexible perovskite solar cells.

Progress of Perovskite Solar Modules

“…A vacuum deposition process has recently released notable results despite a limited number of groups being involved in the previous studies. [ 54,72,73 ] A large PSM based on the thermally co‐deposition of MAI and PbI 2 demonstrated 18.13% of PCE (area = 21 cm 2 ), showing only 10% difference in PCE compared with the unit cell (20.28% of PCE with 0.16 cm 2 ). [ 54 ] Furthermore, the vacuum process allows a flexible substrate to be easily adopted owing to the low temperature process.…”

“…The flexible PSM showed a 13.15% of PCE (area = 16 cm 2 ), which was comparable to that of the rigid substrate, 15.06%. [ 72 ] The HCVD method enables the vapor of organic precursors to be easily controlled during CVD by separate optimization either in tube furnace or vacuum oven. A mixed composition of Cs 0.1 FA 0.9 PbI 2.9 Br 0.1 via HCVD demonstrated a comparably lower PCE of 13.3% from a 0.09 cm 2 ‐sized unit cell due to a negative impact of a vacuum annealing process on underlying SnO 2 layer during the HCVD, [ 61 ] which was more enhanced by adopting RHCVD coupled with a systematic optimization, leading to a PCE of 15.5%.…”

Strategy for large‐scale monolithic Perovskite/Silicon tandem solar cell: A review of recent progress

“…All evaporated PVK devices achieved a champion PCE of 15.06% at 16 cm 2 active area. 102 By optimizing the evaporation process parameters such as deposition rate, substrate temperature, chamber pressure, etc., PCEs of more than 20% have recently been reported with co-evaporated PVK layers. 103 Moreover, 18.13% PCE of a 21 cm 2 PVK module by coevaporation method was reported.…”

“…Lei et al first formed a PbI 2 layer by normal evaporation and then fabricated MAI by flash evaporation to obtain a homogeneous large‐scale PVK film. All evaporated PVK devices achieved a champion PCE of 15.06% at 16 cm 2 active area 102 . By optimizing the evaporation process parameters such as deposition rate, substrate temperature, chamber pressure, etc., PCEs of more than 20% have recently been reported with co‐evaporated PVK layers 103 .…”

Progress in Materials Development for Flexible Perovskite Solar Cells and Future Prospects

“…Lei et al demonstrated a two-step flash-evaporation method where PbI 2 films and MAI films were flash evaporated consecutively to obtain homogeneous large-area perovskite films. [143] With the virtue of this method, they fabricated inverted fPSC module with active area of 16.0 cm 2 and achieved PCE over 13 %. Solution processability and high band gap (~1.6 eV) of perovskites make it suitable for the absorber layer of the top cell in a tandem configuration.…”