Tuning of the Contact Properties for High Efficiency Si/PEDOT:PSS Heterojunction Solar Cells

Heterojunction solar cells (HSCs) featuring half and full contact of poly(3,4-ethylenedioxythiophene):polystyrene (PEDOT:PSS) with pyramid-textured silicon (Si) were thoroughly compared via simulations and experiments, and the following conclusions have been reached: (1) The insufficient electrical passivation inherent to the half contact results in enormous decline in short-circuit current density (J(sc)) and open-circuit voltage (V-oc). (2) For the full-contact HSCs, J(sc) is mainly dependent on the recombination at the rear interface. With tuning of the contact properties from both sides, calculated (experimental) efficiencies of 14.46%/16.89% (13.94%/16.21%) for the half-/full-contact HSCs were finally obtained. A superior power conversion efficiency (PCE) over 21% is further predicted by considering more optimal contact resistance as well as doping concentration of Si. Our findings clarify why textured-Si/PEDOT:PSS HSCs show V-oc and PCE that are inferior to those of planar counterparts in previous reports and further suggest a pathway to fully explore the efficiency potential of Si/PEDOT:PSS hybrid solar cells.