Bulk Passivation and Interfacial Passivation for Perovskite Solar Cells: Which One is More Effective?

Abstract

Perovskite solar cells (PSCs) have emerged as promising candidates for photovoltaic applications because of their superior optoelectronic properties. The power conversion efficiency of 25.5% has been achieved at an astonishing speed from the debut of 3.8%. However, the notoriously poor stability stemming from the solution fabrication process and uncontrollable rapid crystallization limits the commercialization of PSCs. Thus defects are inevitable among the bulk films and interfaces. Herein, recent progress about defects passivation by additive strategy among the bulk film, are discussed. More importantly, the defects passivation strategy for perovskite/electron transport layer and perovskite/hole transport layer interfaces are summarized. Furthermore, how defects passivation and ion migration would affect the stability performance of the perovskite devices are elaborated. Finally, the current challenges for commercialization prospects of perovskite photovoltaic applications are discussed.

23.7% Efficient inverted perovskite solar cells by dual interfacial modification

“…We observe that dual modified devices combine the improvements observed at each interface, resulting in a number of devices with PCE above 22% and a maximum value of 23%. Moreover, for such a dual interfacial modification to find broad use in inverted architecture solar cells, its efficacy needs to be examined in combination with a modification of the bulk of the perovskite layer (38,39). For example, recent reports suggest that the introduction of ionic liquids into the perovskite active layer can significantly increase their stability (40)(41)(42).…”

Improvement Performance of Planar Perovskite Solar Cells by Bulk and Surface Defect Passivation

“…PSCs have garnered increasing concern owing to their economical manufacturing cost and a PCE that has exceeded 25% in the past 11 years. − This improvement in cell performance is due to device optimization via additive engineering and defect passivation and the characteristics of perovskite materials, such as low exciton binding energies and long diffusion pathways. Currently, the PCE of the most advanced perovskite devices trails the Shockley–Queisser limit (33%). − In order to enhance the efficiencies of PSCs, several research strategies have been proposed and studied, including the surface passivation of perovskite films, fine tuning of perovskite components, and additive, solvent, and interface engineering. − Of these, passivation of perovskite films is particularly effective in improving the PSC efficiency. The rationale is that passivating the harmful defects on the interface and crystal boundaries of perovskite layers may significantly hinder the production of recombination centers and suppress hysteresis. , …”

Reduced Recombination Losses in Evaporated Perovskite Solar Cells by Postfabrication Treatment

“…The different remaining nonradiative recombination losses thus still stand as the main present and limiting factors in state-of-the-art perovskite solar cells, and whether bulk or surface recombination truly dominates is currently contested. [23] Most of the aforementioned studies were based on solutionprocessed devices where the solute is annealed to around 100 C to ensure material film crystallization. What is also frequently observed, yet not always reported with scrutiny, is the fact that an additional dwelling time of solution-manufactured devices appears to further improve the efficiency considerably.…”