TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The graphene comprises n sheets, each of which is formed of polycyclic aromatic molecules in which many carbon atoms are bonded to each other in a covalent bond and extend in a first direction (i.e. a direction parallel to the substrate), where n is an integer of greater than or equal to 1, preferably 2-10, and the n sheets are stacked in a second direction perpendicular to the first direction. The graphene-containing layer further comprises a p-type dopant. The p-type dopant comprises nitric acid, gold(III) chloride, hydrochloric acid, nitromethane, sulfuric acid, chloroauric acid, 2,3-dichloro-5,6-dicyanobenzoquinone, acid-terminated small molecules and/or polymeric acid.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The work function of the first surface of the layer haying work function gradient is 4.8-5.3 eV, and the work function of the second surface of the layer having work function gradient is 5.3-6.5 eV. The layer having work function gradient comprises a conductive material and a low-surface-energy material. The low-surface-energy material is a thin film formed of the low-surface-energy material having a surface energy of less than or equal to 30 mN/m and a conductivity of 10-15 to 10-1 S/cm, or a thin film formed of a conductive polymeric composition comprising the low-surface-energy material having a surface energy of less than or equal to 30 mN/m and a conductivity of 10-7 to 10-1 S/cm. The concentration of the low-surface-energy material gradually increases in a direction from the first surface to the second surface. The work function of the first surface of the layer having work function gradient is the same as that of the conductive material, and the work function of the second surface of the layer having work function gradient is the same as that of the low-surface-energy material. The low-surface-energy material comprises at least one fluorine. The low-surface-energy material is a fluorinated polymer having a repeating units of formula (-(CF2-CF2)a-(C(Q1)(F)-CF2)b-) (I), (-(CH2-CH(Q2))p-(CH2-C(Q3)(Q4))q-) (II), or (III). The low-surface-energy material is a fluorinated oligomer having a structure of formula (X-M1fn1-M1hm1-M1ar1-G) (IV). The conductive material comprises polythiophene, polyaniline, polypyrrole, polystyrene, sulfonated polystyrene, poly(3,4-ethylenedioxythiophene), self-doped conductive polymer and/or their derivatives.Q1 = -(O-C(R1)(R2)-C(R3)(R4))c-(OCF2CF2)d-R5, -COOH or -O-R1f-R6;R1-R4 = -F, -CF3, -CHF2 or -CH2F;c, d, x, y, r, s, t = 0-20;R1f = -(CF2)z- or -(CF2CF2O)z-CF2CF2-;z = 1-50;R5, R6, Y1 = -SO3M, -PO3M2 or -CO2M;M = Na+, K+, Li+, H+, CH3(CH2)wNH3+, NH4+, NH2+, NHSO2CF3+, CHO+, C2H5OH+, CH3OH+ or CH3(CH2)wCHO+;w = 0-50;Q2 = H, optionally substituted 5-60C-aryl or -COOH;Q3 = H or optionally substituted 1-20C-alkyl;Q4 = -O-(CF2)rSO3M, -O-(CF2)rPO3M2, -O-(CF2)r-CO2M or -CO-NH-(CH2)s-(CF2)t-CF3;a, m, n = 0-10000000;b = 1-10000000;X = a terminal group;M1f = a unit derived from a fluorinated monomer prepared by condensation reaction of perfluoropolyether alcohol, polyisocyanate and an isocyanate reactive-non-fluorinated monomer;M1h = a unit derived from a non-fluorinated monomer;M1a = a unit having a silyl group of formula -Si(Y4)(Y5)(Y6);Y4-Y6 = 1-20C-alkyl or 6-30C-aryl (both optionally substituted), halo or a hydrolyzable substituent, where at least one of Y4-Y6 is a hydrolyzable substituent;G = a monovalent organic group including a chain transfer agent;n1 = 1-100; andm1, r1 = 0-100, where n+m+r is greater than or equal to 2.