On April 4, a research group led by Professor Takashi Kita and Assistant Professor Shigeo Asahi of the Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University will absorb the spectral components of long-wavelength sunlight and raise the conversion efficiency to 7% or more. Announced that it has developed a technology that can be used.
The theoretical limit of the conversion efficiency of conventional single-junction solar cells is about 30%, and most of the incident solar energy permeates without being absorbed by the solar cell, or the surplus energy of photons becomes heat. Not used.If the conversion efficiency of solar cells exceeds 50%, the power generation cost will drop significantly, and Japan's target power generation cost of 2030 yen / kWh can be achieved in 7.
This time, the research group has developed a new solar cell structure that generates photocurrents using two photons of energy that penetrate the solar cell using a hetero interface consisting of semiconductors with different band caps.This shows the theoretical prediction result that the conversion efficiency is up to 2%, and succeeded in the experimental demonstration of up-conversion (energy boosting) by two photons, which is a unique mechanism of this solar cell.The proven loss suppression effect has reached more than 63 times that of the conventional method using the intermediate band.
In the future, it can be expected to be applied as a new ultra-high efficiency solar cell that can reduce the power generation cost by advancing the design of the solar cell structure using the optimum material and advancing the performance evaluation related to the conversion efficiency.
Paper information:[Nature Communications] Two-step photon up-conversion solar cells (English)
