Precise polarizing and analyzing of laser light with second harmonic generators and sum-frequency converters

For the first time a "nonlinear polarizer" and a "nonlinear analyzer" were simultaneously used for precise polarizing and analyzing of laser light, and linearly polarized laser light of wave length 532 nm, with degree of elliptically less than 6 x 10-9 was generated. Previously [1] we demonstrated a hybrid system consisting of a Glan prism and a frequency doubler employed as a polarizer, while here we report the "completely nonlinear" polarimeter and discuss its advantages

Photoinduced charge transfer in MEH-PPV/Pt₀̣.₇₅C₆₀ donor-acceptor blends

Photoinduced charge transfer (PCT) in donor-acceptor blends of poly[2-methoxy-5-(2'- ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) with coordination oligomer (Pt₀̣ ₇₅C₆₀)n has been studied and compared with that in MEH-PPV/C₆₀ blends. The blends were investigated by using optical absorption, scattering, photoluminescence (PL), photoinduced absorption (PIA), and photocurrent action spectroscopies. We have found that he efficiency of PCT in MEH-PPV/(Pt₀̣.₇₅C₆₀)n blend is somewhat less than in MEH-PPV/C₆₀. This difference is attributed to more enhanced phase separation in MEH-PPV/(Pt₀̣.₇₅C₆₀)n at the nanoscale. Meanwhile, our photocurrent data imply that (Pt₀̣.₇₅C₆₀)n chains could provide a network for collection of photoinduced charges. Remove selecte

Acceptor Energy Offset Manages Ultrafast Recombination Dynamics in Donor-Acceptor Mixtures

We study charge recombination rates in blends of MEH-PPV and a comprehensive set of low molecular-weight fluorine-based acceptors, using visible-pump – IR-probe photoinduced absorption technique. The positions of acceptor’s HOMO-LUMO levels are engineered by addition of different chemical substituents. The results clearly show the exponential scaling of the charge recombination rate with the acceptor LUMO energy. The minimal donor-acceptor LUMO energy difference required to form a CTC state is estimated as ~0.25 eV.

Acceptor Energy Offset Manages Ultrafast Recombination Dynamics in Donor-Acceptor Mixtures

We study charge recombination rates in blends of MEH-PPV and a comprehensive set of low molecular-weight fluorine-based acceptors, using visible-pump – IR-probe photoinduced absorption technique. The positions of acceptor’s HOMO-LUMO levels are engineered by addition of different chemical substituents. The results clearly show the exponential scaling of the charge recombination rate with the acceptor LUMO energy. The minimal donor-acceptor LUMO energy difference required to form a CTC state is estimated as ~0.25 eV