TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Compounds: The compound of perovskite structure is organic-metal halide of perovskite structure. The compound of perovskite structure is a compound of formula (AMX3), an ammonium compound of formula ((R1-NH3+)MX3), and an imidazolide compound of formula ((R2-C3H3N2+-R3)MX3). The metal halide compound comprises an ammonium lead iodine chloride compound (H3NH3PbIxCly), an ammonium lead iodine bromide compound (CH3NH3PbIxBry), ammonium lead chloride bromide compound (CH3NH3PbClxBry) or ammonium lead iodine fluoride compound (CH3NH3PbIxFy), where x is 0-3, y is 0-3, and x+y is 3.A = monovalent organic ammonium ion or Cs+;R1, R2 = 1-24C alkyl, 3-20C cycloalkyl or 6-20C aryl;M = Cu2+, Ni2+, Co2+, Fe2+, Mn2+, Cr2+, Pd2+, Cd2+, Ge2+, Sn2+, Pb2+, or Yb2+;X = F-, Cl-, Br- or I-; andR3 = H or 1-24C alkyl.    TECHNOLOGY FOCUS - POLYMERS - Preferred Compounds: The polymer comprises poly(3-hexylthiophene), poly(2-methoxy-5-(3',7'-dimethyloctyloxyl)-1,4-phenylenevinylene), poly(2-methoxy-5-(2''-ethylhexyloxy)-p-phenylene vinylene), poly(3-octylthiophene), poly(3-decyl thiophene), poly(3-dodecyl thiophene), poly(p-phenylenevinylene), poly(9,9'-dioctylfluorene-co-N-(4-butylphenyl)diphenyl amine), poly(2,1,3-benzothiadiazole-4,7-diyl(4,4-bis(2-ethylhexyl-4H-cyclopenta(2,1-b:3,4-b')dithiophene-2,6-diyl))), poly((4,4'-bis(2-ethylhexyl)dithieno(3,2-b:2',3'-d)silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl)), poly((4,8-diethylhexyloxyl) benzo((1,2-b:4,5-b')dithiophene)-2,6-diyl)-alt-((5-octylthieno(3,4-c)pyrrole-4,6-dione)-1,3-diyl), poly(2,7-(9-(2-ethylhexyl)-9-hexyl-fluorene)-alt-5,5-(4', 7-di-2-thienyl-2',1',3'-benzothiadiazole)), poly(2,7-9,9-(dioctyl-fluorene)-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)), poly((2,7-dioctylsilafluorene)-2,7-diyl-alt-(4,7-bis(2-thienyl)-2,1,3-benzothiadiazole)-5,5'-diyl),poly((4,4'-bis(2- ethylhexyl)dithieno(3,2-b:2',3'-d)silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl), poly((9-(1-octylnonyl)-9H-carbazole-2,7-diyl)-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl), poly(9,9'-dioctylfluorene-co-bis(N,N'-(4,butylphenyl))bis(N,N'-phenyl-1,4-phenylene)diamine, poly(9,9'-dioctylfluorene-co-benzothiadiazole), poly(3,4-ethylenedioxythiophene), poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate), poly(triarylamine) and poly(4-butylphenyl-diphenyl-amine). The hole transport layer comprises an additive consisting of tertiary butyl pyridine and lithium bis(trifluoro methanesulfonyl)imide. The polymer comprises thiophene-based polymers, paraphenylene vinylene, carbazole and triphenylamine, and is a nitrogen compound of formula ((-R4-N(R5)-R6-)n).R4, R6 = 6-20 arylene, preferably phenylene, naphthalene, biphenylene, terphenylene, indenylene, fluorenylene, triphenylenylene, pyrenylene, perylenylene, crycenylene, naphthacenylene or fluorantenylene;R5 = 1-30C alkyl, 6-30C aryl (both optinally substituted), halo, 2-30C heteroaryl, 5-7-membered cycloalkyl, heterocycloalkyl, 3-30C cycloalkyl, 2-30C alkenyl, 2-30C alkynyl, cyano, carbazolyl, or nitro, preferably phenyl, naphthyl, biphenyl, terphenyl, anthryl, indenyl, fluorenyl, phenanthryl, triphenylenyl, carbonyl, perylenyl, chrysenyl, naphthacenyl or fluoranthene; andn = 2-100000.