Reduced Charge Transfer Exciton Recombination in Organic Semiconductor Heterojunctions by Molecular Doping

Ultrafast electron and hole transfer in bulk heterojunctions of low-bandgap polymers

“…Initial processes of photon absorption, intramolecular chargetransfer (ICT) exciton formation and their following dissociation/ recombination form the basis for the device operation. These early-time dynamics in pristine pushpull polymers are quite complex and include a number of competitive processes [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. The initial ultrafast photophysics of polymer-based bulk heterojunctions (BHJs) with fullerenes are even more complicated and depend on a number of factors such as the particular polymer structure, acceptor type, donor-acceptor phase separation known as BHJ morphology [25] etc.…”

Ultralow Doping in Organic Semiconductors: Evidence of Trap Filling

“…Recently, increased attention has been placed on the role that electronic states that extend into the gap of the semiconductors play in charge-carrier transport, interface formation and overall device performance [1][2][3][4][5]. Organic semiconductors are characterized by relatively small electronic couplings [6]; as a result, even a moderate energy or structural disorder leads to the localization of all electronic states.…”

Structural correlations in the generation of polaron pairs in low-bandgap polymers for photovoltaics

“…Light absorption by the polymer has been largely improved towards the near infrared (NIR) spectral region by the introduction of low-bandgap co-polymers 4,5 . Exciton dissociation, however, remains to be understood and has recently been the subject of several investigations [6][7][8][9][10] .…”