Semiconductor organic-inorganic nanocomposites: From synthesis to packing at the air/water interface and photovoltaic application

Nanocomposites of poly(3-hexylthiophene)-cadmium selenide (P3HT-CdSe) were synthesized by directly grafting vinyl terminated P3HT onto [(4-bromophenyl)methyl]dicotylphosphine oxide (DOPO-Br)-functionalized CdSe quantum dot (QD) surfaces via a mild palladium-catalyzed Heck coupling, thereby dispensing with the need for ligand exchange chemistry. The resulting P3HT-CdSe nanocomposites possess a well-defined interface, thus significantly promoting the dispersion of CdSe within the P3HT matrix and facilitating the electronic interaction between these two components. The P3HT-CdSe nanocomposites at the air/water interface formed via Langmuir isotherms were explored for the first time. The P3HT-CdSe nanocomposites displayed a high pressure plateau in the Langmuir isotherm, illustrating their complex packing at the air/water interface. Furthermore, photovoltaic devices fabricated from the LB depositions of the P3HT-CdSe nanocomposites exhibited a relatively high short circuit current, I_SC, while maintaining a thin film profile. These studies provide insights into the fundamental behaviors of semiconductor organic f{inorganic nanocomposites confined at the air/water interface as well as in the active layer of an organic-based photovoltaic device.