{'fraction_non_alphanumeric': 0.05804749340369393, 'fraction_numerical': 0.00395778364116095, 'mean_word_length': 4.793893129770993, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Modeling of bulk and bilayer organic heterojunction solar cells

Solar cells require symmetry-breaking features such as built-in electrostatic fields and/or effective fields. We examine an organic heterojunction structure with no built-in field and explore the origins of its current-voltage characteristics and open circuit voltage ( V OC ) . Two behaviors are found: (1) V OC = V I + m [(HOMO(D) - (LUMO(A)] where m ≈ 1 , the intercept ( V I ) is determined by interface recombination kinetics, HOMO(D) is the donor highest occupied molecular orbital, and LUMO(A) is the acceptor lowest unoccupied molecular orbital; (2) if interface recombination is suppressed, V OC is controlled by bulk/contact recombination and is not dependent upon HOMO(D) - LUMO(A).