The Light-Induced Field-Effect Solar Cell Concept – Perovskite Nanoparticle Coating Introduces Polarization Enhancing Silicon Cell Efficiency
Y. Wang, Z. Xia, L. Liu, W. Xu, Z. Yuan, Y. Zhang, H. Sirringhaus, Y. Lifshitz, S.-T. Lee, Q. Bao, and B. Sun
Advanced Materials 29, 1606370 (2017)
Solar cell generates electrical energy from light one via pulling excited carrier
away under built-in asymmetry. Doped semiconductor with antireflection layer
is general strategy to achieve this including crystalline silicon (c-Si) solar cell.
However, loss of extra energy beyond band gap and light reflection in particular
wavelength range is known to hinder the efficiency of c-Si cell. Here, it
is found that part of short wavelength sunlight can be converted into polarization
electrical field, which strengthens asymmetry in organic-c-Si heterojunction
solar cell through molecule alignment process. The light harvested
by organometal trihalide perovskite nanoparticles (NPs) induces molecular
alignment on a conducting polymer, which generates positive electrical
surface field. Furthermore, a “field-effect solar cell” is successfully developed
and implemented by combining perovskite NPs with organic/c-Si heterojunction
associating with light-induced molecule alignment, which achieves an
efficiency of 14.3%. In comparison, the device with the analogous structure
without perovskite NPs only exhibits an efficiency of 12.7%. This finding provides
a novel concept to design solar cell by sacrificing part of sunlight to provide
“extra” asymmetrical field continuously as to drive photogenerated carrier
toward respective contacts under direct sunlight. Moreover, it also points out
a method to combine promising perovskite material with c-Si solar cell.