For any emerging photovoltaic technology to become commercially relevant, both its power conversion efficiency and photostability are key parameters to be fulfilled. Colloidal quantum dot solar cells are a solution-processed, low-cost technology that has reached an efficiency of about 9% by judiciously controlling the surface of the quantum dots to enable surface passivation and tune energy levels. However, the role of the quantum dot surface on the stability of these solar cells has remained elusive. Here we report on highly efficient and photostable quantum dot solar cells with efficiencies of 9.6% (and independently certificated values of 8.7%). As a result of optimized surface passivation and the suppression of hydroxyl ligands—which are found to be detrimental for both efficiency and photostability—the efficiency remains within 80% of its initial value after 1,000 h of continuous illumination at AM1.5G. Our findings provide insights into the role of the quantum dot surface in both the stability and efficiency of quantum dot solar cells.

Nature Energy 1, Article number: 16035 (2016)
doi:10.1038/nenergy.2016.35

http://www.nature.com/articles/nenergy201635

任何一种新兴的光伏技术要想实现商业应用，都必须同时满足高效率和高稳定性两个条件。胶体量子点太阳能电池是一种可以溶液加工的低成本电池技术，目前最高效率已经超过9%。这种电池需要精细调控量子点表面的钝化以及能级水平。不过，量子点表面对于电池稳定性的影响还是不很清楚。Cao等人报道了一种高效、光稳定的量子点太阳能电池，其效率可达到9.6%。他们发现表面钝化和羟基配体对于电池效率和稳定性都起到决定性作用。通过对这两者的优化，他们制备的电池在连续1000小时的光照下，依然可以保持80%以上的效率。（新材料在线）