Surface\nEngineering of Low-Temperature Processed Mesoporous TiO₂ via Oxygen Plasma for Flexible Perovskite Solar Cells

Abstract

A major\nproblem in the application of mesoporous TiO₂ as an electron\ntransport layer for flexible perovskite solar cells is that a high-temperature\nsintering process is required to remove organic additives from the\nTiO₂ layer. A facile oxygen plasma process is herein demonstrated\nto fabricate mesoporous-structured perovskite solar cells with significant\nphotovoltaic performance at low temperatures. When the low-temperature\nprocessed TiO₂ layer is modified via oxygen plasma, the\norganic additives in the TiO₂ layer that hinder the charge\ntransport process are successfully decomposed. The oxygen plasma treatment\nimproves the wettability and infiltration of the perovskite layer\nand also passivates the oxygen vacancy related traps in TiO₂. Hence, the oxygen plasma treatment evidently enhances charge extraction\nand transport, thereby improving photovoltaic performance and decreasing\nhysteresis.