Ultra thin perovskite solar cell for over 30% tandem solar cell and light confining bonding technology

2020 Fiscal Year Final Research Report

• Project/Area Number: 16H02451
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Energy engineering
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Ihara Manabu 東京工業大学, 物質理工学院, 教授 (90270884)
• Project Period (FY): 2016-04-01 – 2021-03-31
• Keywords: solar cell / tandem solar cell / monocrystalline thin Si / perovskite / passivation

Outline of Final Research Achievements

To achieve the solar cell with above 30% conversion efficiency, to develop the tandem solar cells which have the multiple power generation layers is necessary with different bandgaps with minimizing the efficiency loss at top cells, bottom cells and their interface. The method to independently control the grain size of perovskite thin film was developed and the effect of grain size on the efficiency of perovskite solar cell was clarified. To reduce the cost of monocrystalline Si bottom cell, the fabrication process of wafer level thin monocrystalline Si was developed by nanometer-level smoothing of porous Si underlayer and the epitaxy by rapid vapor deposition on it. As for the Si/perovskite interface, the effect of thermal annealing process on the TiO2 interlayer was investigated which works as the passivation layer of the bottom Si surface and the electron transfer layer of perovskite top cell.

Free Research Field

化学工学

Academic Significance and Societal Importance of the Research Achievements

太陽電池の効率30%超を達成するためのタンデム太陽電池の開発は、脱炭素電源の主力化に向けて重要である。また、本研究の各項目において得られた学術的な意義は大きい。ペロブスカイト太陽電池においては、これまでできていなかった、発電効率に他の要素を一定にして結晶粒径のみを変化させる手法を確立し、発電特性との直接の関連性をはじめて明らかにした。Si単結晶薄膜製造プロセスでは、結晶化しながら急速に堆積する本プロセスにおいて、原子レベルの凹凸の違いが得られる単結晶の欠陥密度に大きな影響を与えるという、結晶学的に重要な知見となった。