Ordered Materials for Organic Electronics and Photonics

Abstract

We present a critical review of semiconducting/light emitting, liquid crystalline materials and their use in electronic and photonic devices such as transistors, photovoltaics, OLEDs and lasers. We report that annealing from the mesophase improves the order and packing of organic semiconductors to produce state-of-the-art transistors. We discuss theoretical models which predict how charge transport and light emission is affected by the liquid crystalline phase. Organic photovoltaics and OLEDs require optimization of both charge transport and optical properties and we identify the various trade-offs involved for ordered materials. We report the crosslinking of reactive mesogens to give pixellated full-colour OLEDs and distributed bi-layer photovoltaics. We show how the molecular organization inherent to the mesophase can control the polarization of light-emitting devices and the gain in organic, thin-film lasers and can also provide distributed feedback in chiral nematic mirrorless lasers. We update progress on the surface alignment of liquid crystalline semiconductors to obtain monodomain devices without defects or devices with spatially varying properties. Finally the significance of all of these developments is assessed.

High Birefringence Liquid Crystals

“…They are connected with telecommunication devices needs or nondestructive microwaves apparatus to control goods and people [19], cholesteric lasers [20,21], manufacturing tunable metamaterial [22][23][24][25]. Different devices such as tunable spatial modulators for light and laser beam steering and for holography [26][27][28][29][30][31][32][33], switchable phase shifters [34][35][36], various types of tunable filters which select or remove bands [37][38][39][40], tunable capacitors [41], antennas [42], lenses [43,44] were manufactured, and others such as photonic fiber [45] (see also, for more information, reviewed papers [46,47]). For these purposes, different high birefringence materials from 0.2 to more than 0.5 are now available [48][49][50][51][52], but further development and improvement of their properties is still necessary.…”

Elasticity-dependent self-assembly of micro-templated chromonic liquid crystal films

“…As a result, their mesophases differ significantly from thermotropic and amphiphilic lyotropic liquid crystals. Patterned films of LCLCs have a wide variety of emerging applications distinct from other types of liquid crystals, including inexpensive polarizing films, [12][13][14] holographic displays, 15,16 organic electronics and solar cells, 17,18 biosensors, 19,20 , aqueous colloidal, nanotube and bacterial assembly, [21][22][23][24][25] and precursors to structured graphene-based materials. 26,27 LCLCs also offer useful attributes for fundamental investigation of the effects of elasticity on self-assembly behavior, since their elastic properties can be tuned via control of mesogen concentration, 28 depletants and ions.…”

The Harvard Clean Energy Project: Large-Scale Computational Screening and Design of Organic Photovoltaics on the World Community Grid

“…OPVs have great potential in two important areas: they promise simple, low-cost, and highvolume production [16] as well as the prospect of merging the unique flexibility and versatility of plastics with electronic features. OPVs can be processed via roll-to-roll printing [17,18]; there is active research in sprayable and paintable materials [19][20][21][22]; OPVs can be semitransparent [23], variously colored [24], they are lightweight [14], and can essentially be molded into any shape [25]. These properties make OPVs a promising candidate to achieve the ubiquitous harvesting of solar energy [26,27], with building-integrated [28][29][30] and ultraportable applications [31][32][33] as primary targets.…”