Upconversion semiconductor interfaces by wafer bonding for photovoltaic applications.

Efficient use of incident sunlight is an important key issue for the improvement of solar cell performance. Here, we propose and experimentally demonstrate photon upconversion material mediated semiconductor bonding as a concept of interfacial functionalization. Our wavelength-converting semiconductor interface comprises rare earth doped upconversion nanoparticles embedded in a hydrogel matrix. Advantageously, the bonding process is conducted at room temperature in ambient air. As a proof of principle, photocurrent enhancement in bonded Si solar cells is demonstrated. Our technical scheme could be useful to improve the performance and structural flexibility of various optoelectronic devices by delivering the preferred frequency to each of the optical components. [ABSTRACT FROM AUTHOR]