posted on 2023-11-01, 12:40authored byYu-Chan Tai, Wen-Yen Tzeng, Jhen-Dong Lin, Yi-Hou Kuo, Fu-Xiang Rikudo Chen, Ruei-Jhe Tu, Ming-Yang Huang, Shyh-Shii Pai, Nick Weihan Chang, Sheng-Yang Tseng, Chi Chen, Chun-Liang Lin, Atsushi Yabushita, Shun-Jen Cheng, Chih-Wei Luo
The energy transfer (ET) between organic molecules and
semiconductors
is a crucial mechanism for enhancing the performance of semiconductor-based
optoelectronic devices, but it remains undiscovered. Here, ultrafast
optical pump–probe spectroscopy was utilized to directly reveal
the ET between organic Alq3 molecules and Si semiconductors.
Ultrathin SiO2 dielectric layers with a thickness of 3.2–10.8
nm were inserted between Alq3 and Si to prevent charge
transfer. By means of the ET from Alq3 to Si, the SiO2 thickness-dependent relaxation dynamics of photoexcited carriers
in Si have been unambiguously observed on the transient reflectivity
change (ΔR/R) spectra, especially
for the relaxation process on a time scale of 200–350 ps. In
addition, these findings also agree with the results of our calculation
in a model of long-range dipole–dipole interactions, which
provides critical information for developing future optoelectronic
devices.