Simple technique for determining the refractive index of phase-change materials using near-infrared reflectometry: publisher’s note
Optical Materials Express Optica Publishing Group 10:8 (2020) 1826
Simple technique for determining the refractive index of phase-change materials using near-infrared reflectometry
Optical Materials Express The Optical Society 10:7 (2020) 1675-1675
Simple technique for determining the refractive index of phase-change materials using near-infrared reflectometry
Optical Materials Express 10:7 (2020) 1675-1686
Ultrafast Charge Dynamics in Dilute-Donor versus Highly Intermixed TAPC:C60 Organic Solar Cell Blends.
The journal of physical chemistry letters (2020)
Abstract:
Elucidating the interplay between film morphology, photophysics, and device performance of bulk heterojunction (BHJ) organic photovoltaics remains challenging. Here, we use the well-defined morphology of vapor-deposited di-[4-(N,N-di-p-tolyl-amino)-phenyl]cyclohexane (TAPC):C60 blends to address charge generation and recombination by transient ultrafast spectroscopy. We gain relevant new insights to the functioning of dilute-donor (5% TAPC) fullerene-based BHJs compared to molecularly intermixed systems (50% TAPC). First, we show that intermolecular charge transfer (CT) excitons in the C60 clusters of dilute BHJs rapidly localize to Frenkel excitons prior to dissociating at the donor:acceptor interface. Thus, both Frenkel and CT excitons generate photocurrent over the entire fullerene absorption range. Second, we selectively monitor interfacial and bulk C60 clusters via their electro-absorption, demonstrating an energetic gradient that assists free charge generation. Third, we identify a fast (< 1 ns) recombination channel, whereby free electrons recombine with trapped holes on isolated TAPC molecules. This can harm the performance of dilute solar cells, unless the electrons are rapidly extracted in efficient devices.In Situ Observations of the Growth Mode of Vacuum-Deposited alpha-Sexithiophene
JOURNAL OF PHYSICAL CHEMISTRY C 124:22 (2020) 11863-11869