TECHNOLOGY FOCUS - ELECTRONICS - Preferred System: The system further comprises a recombination layer. In the system, at least one of the first and second electrodes is a mesh electrode. The recombination layer comprises a p-type semiconductor material and an n-type semiconductor material. The p-type and n-type semiconductor materials are blended into one layer. The recombination layer comprises two layers, one layer comprising the p-type semiconductor material and the other layer comprising the n-type semiconductor material.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The first comonomer repeat unit comprises a cyclopentadithiophene moiety of formula (I), or silacyclopentadithiophene moiety of formula (II).R1-R4=H, 1-20C alkyl, 1-20C alkoxy, 3-20C cycloalkyl, 1-20C heterocycloalkyl, aryl, heteroaryl, halo, CN, OR, C(O)R, C(O)OR, or SO2R;R=H, 1-20C alkyl, 1-20C alkoxy, aryl, heteroaryl, 3-20C cycloalkyl, or 1-20C heterocycloalkyl;R5 and R6=H, 1-20C alkyl, 1-20C alkoxy, 3-20C cycloalkyl, 1-20C heterocycloalkyl, aryl, heteroaryl, halo, CN, OR, C(O)R, C(O)OR, or SO2R; andR5a, R6a, R7, and R8=H, 1-20C alkyl, 1-20C alkoxy, 3-20C cycloalkyl, 1-20C heterocycloalkyl, aryl, heteroaryl, halo, CN, OR, C(O)R, C(O)OR, or SO2R.The second comonomer repeat unit comprises a moiety selected from benzothiadiazole, thiadiazoloquinoxaline, cyclopentadithiophene oxide, benzoisothiazole, benzothiazole, thiophene oxide, thienothiophene, thienothiophene oxide, dithienothiophene, dithienothiophene oxide, tetrahydroisoindole, fluorene, silole, cyclopentadithiophene, thiazole, selenophene, thiazolothiazole, cyclopentadithiazole, naphthothiadiazole, thienopyrazine, silacyclopentadithiophene, oxazole, imidazole, pyrimidine, benzoxazole, and benzimidazole (preferably benzothiadiazole, thiophene, thiophene dioxide, or thiazole moiety). The second comonomer repeat unit comprises 34 structures as given in the specification, e.g. 2,1,3-benzothiadiazole-4,7-diyl (substituted at 5- and 6-positions by R5 and R6, respectively), (1,2,5)thiadiazolo(3,4-g)quinoxaline-4,9-diyl (substituted at 6- and 7-positions by R5 and R6, respectively), 1,7-dioxo-4H-thieno(3',2':4,5)cyclopenta(1,2-b)thiophene-2,6-diyl (4-positions disubstituted by R5 and R6), 1-oxo-4H-thieno(3',2':4,5)cyclopenta(1,2-b)thiophene-2,6-diyl (4-positions disubstituted by R5 and R6), 2,1-benzisothiazole-4,7-diyl (substituted at 3-, 5- and 6-positions by R7, R5 and R6, respectively), benzothiazole-4,7-diyl (substituted at 2-, 5- and 6-positions by R7, R5 and R6, respectively), or 1,1-dioxothiophene-2,5-diyl (substituted at 3- and 4-positions by R5 and R6, respectively). The second comonomer repeat unit comprises at least three (preferably at least five) thiophene moieties, where at least one of the thiophene moieties is substituted by 1-20C alkyl, 1-20C alkoxy, aryl, heteroaryl, 3-20C cycloalkyl, or 3-20C heterocycloalkyl). The polymer further comprises a third comonomer repeat unit. The third comonomer repeat unit further comprises a thiophene moiety or a fluorene moiety, where the thiophene or fluorene moiety is substituted with at least one substituent selected from the group consisting of 1-20C alkyl, 1-20C alkoxy, aryl, heteroaryl, 3-20C cycloalkyl, and 3-20C heterocycloalkyl. Preferred Definitions:    R1, R2, R5a and R6a=hexyl, 2-ethylhexyl, or 3,7-dimethyloctyl.