Molecular Modeling of Hot Electron Transfer for Solar Energy Conversion

PI Hanning Chen, George Washington University
Project Description

The  Sun  radiates  ~200,000  TW  of  power  onto  the  Earth;  about  1,000  times  the  yearly  global power demand. Because of this bounty, technology that converts solar energy into a usable energy (e.g., electricity) stands out among renewable energy technologies.  Solar cell technology is one such technology and takes energy irradiated from the sun and converts it into  usable  electrical  energy.  At  the  heart  of  solar  cell  technology  is  light-­matter  interactions;  light  irradiated  from  the  sun  interacts  with  matter  to  excite  electrons.  The excited electrons can then enter conduction bands, move in a current, and create electricity. The  physics  of  light-­matter  interactions  determine  how  efficient  light  energy  can  be  converted  into  electrical  energy,  with  current  theory  limiting  the  efficiency  to  33%. However,  a  theory  of  ‘hot-­carrier  solar  cells’  predicts  that  under  special  non-­equilibrium  circumstances, efficiencies of up to 66% could be achieved. Realizing 66% efficiencies could drastically  push  solar  cell  technology  forward,  yet  in  spite  of  its  theoretical  feasibility,  experimental implementation is still in its infancy. This project supports development of a computational paradigm based on vibrationally resolved electron transfer theory to guide the experimental implementation and optimization of the emerging hot-­carrier solar cells. In  addition,  this  framework  will  be  implemented  into  a  highly  parallel  open-­source  molecular  simulation  package  that  is  freely  available  to  the  scientific  community  for research and education. Outcomes of this project will advance our understanding of light-­matter  interactions  in  photovoltaics  and  could  provide  key  insights  to  realizing  next generation solar cell technology.