Methodologies toward Highly Efficient Perovskite Solar Cells

Abstract

A perovskite solar cell (PSC) employing an organic-inorganic lead halide perovskite light harvester, seeded in 2009 with power conversion efficiency (PCE) of 3.8% and grown in 2011 with PCE of 6.5% in dye-sensitized solar cell structure, has received great attention since the breakthrough reports ≈10% efficient solid-state PCSs demonstrating 500 h stability. Developments of device layout and high-quality perovskite film eventually lead to a PCE over 22%. As of October 31, 2017, the highest PCE of 22.7% is listed in an efficiency chart provided by NREL. In this Review, the methodologies to obtain highly efficient PSCs are described in detail. In order to achieve a PCE of over 20% reproducibly, key technologies are disclosed from the viewpoint of precursor solution chemistry, processing for defect-free perovskite films, and passivation of grain boundaries. Understanding chemical species in precursor solution, crystal growth kinetics, light-matter interaction, and controlling defects is expected to give important insights into not only reproducible production of high PCE over 20% but also further enhancement of the PCE of PCSs.

CH3NH3PbI3 and HC(NH2)2PbI3 Powders Synthesized from Low‐Grade PbI2: Single Precursor for High‐Efficiency Perovskite Solar Cells

“…[30] Upon dissolving the d-phase and a-phaseF APbI 3 powders in DMSO/ DMF solvent, the color of the solution containing the dissolved d-phase FAPbI 3 powder (PbI 2 /FAI = 1:1) was transparent yellow, whereas ab rown color was observed for the solution with the a-phase FAPbI 3 powder (Figure 7a). [30] Upon dissolving the d-phase and a-phaseF APbI 3 powders in DMSO/ DMF solvent, the color of the solution containing the dissolved d-phase FAPbI 3 powder (PbI 2 /FAI = 1:1) was transparent yellow, whereas ab rown color was observed for the solution with the a-phase FAPbI 3 powder (Figure 7a).…”

“…[16] Owing to these superior properties, organolead halide perovskites have applicationst hat can be extended to X-ray detectors, lightemitting diodes, lasing, water splitting, and memristors, which also show excellent characteristics. [16][17][18][19][20][21][22][23] Despite the wide area of applications, the superior properties of PSCs critically rely on the quality of the perovskite layer, which depends on the experimental environment, such as the moisturel evel and/or temperature; [24][25][26][27][28] perovskite-coating procedures, including Lewis acid-base adduct approacha nd solvente ngineering; [8,10,29,30] and the purity of the raw materials. [31] Althoughc oating procedures to obtainh igh-quality perovskite seem to be established, because the PCEs of some PSCs surpass those of high-efficiency thin-film technologies (CIGS and CdTe), high PCEs can only be achieved by using highly pure PbI 2 .T he requirement for ah igh purity exceeding 99.99 %i sd ue to the fact that undesired materials in the raw materials, such as impurities, hydrated sources, and stabilizers, have often been found to be trap states,r esulting in as erious decreasei nc harge-carrier lifetimea nd the PL yield.…”

Ag/In lead‐free double perovskites

“…The replacement of the harmful lead (Pb) in lead halide perovskites for efficient, yet low cost solar cells and LEDs is one of the most pressing issues in todays' materials science. In fact, solar cells and visible light LEDs based on lead halide perovskites have nowadays reached 25% and more efficiency, and outdoor operational capability is currently tested in view of near‐future industrial production and commercialization.…”

Interface Engineering in n‐i‐p Metal Halide Perovskite Solar Cells

“…The solution‐processed method has become increasingly successful owing to a deep understanding of precursor solution chemistry. The type and amount of precursor and solvent can greatly influence the rate of solvent evaporation and chemical constituent diffusion, thereby determining the growth kinetics and final morphologies of MHP films . In addition, technique parameters (e.g., precursor solution concentration; antisolvent dropping; and annealing temperature, time, and atmosphere) affect the morphology, crystallinity, defect concentration, and physical properties of MHPs.…”