Improved stability - the game changer for perovskite photovoltaics

Organo-lead halide perovskite materials, commonly used in high-efficiency perovskite solar cells, are materials that can easily decompose in moisture conditions. They cannot survive even for one day without proper encapsulation. Due to the lead contained, perovskite solar cells may have limited applications as lead is not allowed in consumer electronic devices according to RoHS. Other potential applications require long-lifetime solar cells. Therefore, stability is the bottle neck for potentially large deployment of perovskite solar cells.

Recently, Yang Yang group from UCLA published a perovskite solar cell device with two layers of metal oxide as electron and hole transporting layers in Nature Nanotechnology. In this p-i-n structure, metal oxide layers also prevent perovskite from degradation. After 60 days storage in air at room temperature, the device retained 90% of its initial efficiency (14.8% efficiency). Compared with the control device with organic transport layers (12.8% efficiency in the beginning), which degraded completely within 5 days.

Since the first introduction of perovskite solar cells in 2006, with an efficiency of 2.2%, they have experienced a remarkable learning curve, to the certified record of 20.1% at the end of 2014. The efficiency improvement of any other photovoltaic (PV) technologies are not comparable with perovskite's. In addition, the low-cost and abundant materials used as the active layer, as well as the potential cheap manufacturing methods with solution processing capability are also advantages. Unlike the bulky, heavy, rigid and opaque silicon solar cells which dominate the current PV markets. Perovskite solar cells can provide many value propositions including light-weight, flexibility, semi-transparency etc. They have attracted tremendous attention and this field becomes "crazy crowded" in the academia. Traditional PV companies also pay close attention to the new materials to make sure they will not lag behind when breakthrough is achieved.

So far stability is one of the major issues in perovskite solar cells. Successfully tackling this issue may unlock perovskite solar cells as a game-changer. For market, technology and player analysis, please refer to IDTechEx's report The Rise of Perovskite Solar Cells 2015-2025, Technology, Status and Market and attend Energy Harvesting and Storage conference at IDTechEx Show! Santa Clara, California (18-19 November 2015) with its 250 exhibitors, 3000+ paying delegates, nine parallel conferences and, on the days before and after, 23 optional masterclasses on these and associated topics with visits to centres of excellence. Weihua Solar, a Chinese company currently working on and commercialization of perovskite solar cells and building the pilot power station will talk at IDTechEx's conference in Santa Clara.