Twisted Organic Semiconductor Crystals for Chiroptoelectronics

We present crystal twisting, a common albeit little known phenomenon in molecular crystals, as a generalizable strategy to repurpose optically inactive organic semiconductors for chiroptoelectronics. This phenomenon is not limited to specific chemical structures or crystal space groups - twisting has been observed in inorganic, polymer, and small molecule crystals grown from vapor, solutions and melts. Because crystal twisting introduces repeating patterns of crystal orientations perpendicular to the substrate surface as crystals twist about the fast growth direction, <hkl>-dependent material properties are likewise patterned on the microns to millimeter length scale. Twisting also imparts chirality - crystals twist either clockwise or counterclockwise about the growth direction - rendering them optically active. The commonality of crystal twisting enables potentially hundreds of centrosymmetric organic semiconductors designed over the past fifty years to be incorporated into devices that discriminately transmit, emit and detect circularly polarized light. Here we characterize the (chir)optoelectronic properties of several molecular semiconductors, including triisopropylsilylethynyl anthradithiophene (TIPS ADT) and tetrathiafulvalene (TTF), and test their performance in resistors, transistors and photodetectors.