TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Device: In the device, the donor material is an exciton donor material and the acceptor material is an exciton acceptor material. The donor material is an electron donor material and the acceptor material is an electron acceptor material. The acceptor material comprises an inorganic material, such that the donor material and the acceptor material form an organic-inorganic heterojunction. The acceptor material comprises silicon. The device further comprises an exciton blocking layer, where the exciton blocking layer comprises a conducting polymer; and a triplet emitter species in electronic or excitonic communication with the donor material, where the triplet emitter species is phosphorescent in the range of 700-1100 nm. The triplet emitter species comprises a metal species. Alternatively, the device comprises: a donor material comprising an organic compound having a singlet energy and a triplet energy, where the singlet energy is about two times greater than the triplet energy; an acceptor material having a first side in physical contact with the donor material, and a second, opposing side; and at least one electrical contact in physical contact with the second, opposing side of the acceptor material, where the donor material is not in physical contact with an electrical contact. The organic compound has a singlet energy of greater than 2.2 eV and/or a triplet energy of greater than 1.1 eV. In a second alternative case, the device comprises: a donor material comprising an organic compound; an acceptor material with a first side in physical contact with the donor material, and a second, opposing side; and at least one electrical contact in physical contact with the second, opposing side of the acceptor material, where the organic compound is not pentacene. In a third alternative case, the device comprises: a singlet fission material comprising an organic compound having a singlet energy and a triplet energy, where the singlet energy is about two times greater than the triplet energy; a triplet emitter species in electronic or excitonic communication with the singlet fission material; and a silicon material in optical or excitonic communication with the triplet emitter species. The singlet fission material comprises an optionally substituted polyacene species or an optionally substituted polyene species. The device further comprises at least one electrical contact in physical contact with the silicon material and, optionally, with the singlet fission material. In a fourth alternative case, the device comprises: a singlet fission material; an organic electron acceptor material or an organic electron donor material in contact with the singlet fission material; and an inorganic material in physical contact with the singlet fission material. The singlet fission material is an electron donor material and the inorganic material is an electron acceptor material. The singlet fission material comprises an organic compound having a singlet energy and a triplet energy, where the singlet energy is about two times greater than the triplet energy. The singlet fission material does not comprise pentacene. The device further comprises at least one electrical contact in physical contact with the inorganic material and, optionally, with the singlet fission material.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The optionally substituted polyacene species is an optionally substituted tetracene or an optionally substituted pentacene. The optionally substituted polyacene species is tetracene, rubrene, dithienyl tetracene, bis(triisopropylsilyl ethynyl) (TIPS)-tetracene, dibithienyl tetracene, diphenyl tetracene, terbutyl rubrene, pentacene, TIPS-pentacene, diphenyl pentacene, dibiphenyl pentacene, dithienyl pentacene, or dibithienyl pentacene. The optionally substituted polyene species is diphenylbutadiene, diphenylhexatriene, or diphenyloctatetraene. The optionally substituted polyacene comprises a heteroatom, and is diphenyl isobenzofuran. The acceptor material comprises fullerenes, nanotubes, and/or nanorods, any of which are optionally substituted. The acceptor material is an optionally substituted fullerene, preferably C60. The triplet emitter species is a quantum dot or an optionally substituted porphine. The triplet emitter species comprises platinum (Pt)(II) meso-tetraphenyl tetrabenzoporphine, Pt(II) tetraphenyl benzoporphine, Pt(II) octaethyl porphine, palladium (Pd)(II) tetrabenzoporphine, Pt(II) meso-tetra(pentaflurophenyl) porphine, Pt(II) tetrabenzoporphine, Pd(II) meso-tetraphenyl porphine, Pt(II) aza-triphenyltetrabenzoporphyrin, Pt(II) tetraphenyltetranaphtho(2,3)porphyrin, lead sulfide (PbS) quantum dots, lead selenide (PbSe) quantum dots, cadmium sulfide (CdS) quantum dots, cadmium selenide (CdSe) quantum dots, or indium arsenide (InAs) quantum dots.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The conducting polymer comprises polyaniline, polythiophene, polypyrrole, polyphenylene, polyarylene, poly(bisthiophene phenylene), a ladder polymer, poly(arylene vinylene), poly(arylene ethynylene), metal derivatives, or substituted derivatives. The conducting polymer is polythiophene or a substituted derivative. The exciton blocking layer comprises poly(3-hexylthiophene).