NOVELTY - A thermoelectric conversion element (1) comprises electrode (13), thermoelectric conversion layer (14) and electrode (15) on base material (12, 16). The thermoelectric conversion layer contains conductive nano-material and at least one compound chosen from sulfonium salt (1a) or (1b), phosphonium salt (2a) or (2b), and quaternary ammonium salt (3a) or (3b).    USE - Thermoelectric conversion element is used for forming thermoelectric conversion material, articles for thermoelectric generations, and power supply for sensors (all claimed). Uses include but are not limited to Peltier device, wrist watch, power supply for remote district, and space power supply.    ADVANTAGE - The thermoelectric conversion element has excellent adhesiveness, and thermoelectric conversion characteristics, and provides thermoelectric conversion material having excellent dispersibility of conductive nano-material, and thermoelectromotive force, and power supply for sensors and articles for thermoelectric generations having excellent thermoelectric conversion characteristics.    DETAILED DESCRIPTION - A thermoelectric conversion element comprises electrode (13), thermoelectric conversion layer and electrode (15) on base. The thermoelectric conversion layer contains conductive nano-material and at least one compound chosen from sulfonium salt of formula (1a) or (1b), phosphonium salt of formula (2a) or (2b), and quaternary ammonium salt of formula (3a) or (3b).    X-=counter anion;    R11-R13=alkyl or heteroaryl, in which R12 and R13 optionally combines with each other to form a ring;    n=2 or 3;    Xp-=p-valent counter anion;    p=1-3;    k=1-3;    n=kp;    L=n-valent linking group or single bond;    R21-R24=alkyl, aryl or heteroaryl, in which any two of R21-R24 optionally combines with each other to form a ring;    A=nitrogen-containing heterocyclyl;    R31, R32=alkyl, aryl or heteroaryl, in which R31 optionally combines with A to form a ring;and    m=0 or 1.    (i) when m is 0, A is a nitrogen-containing heteroaryl; and (ii) when m is 1, A is nitrogen-containing aliphatic heterocyclyl. An INDEPENDENT CLAIM is included for thermoelectric conversion material, which comprises at least one compound chosen from sulfonium salt of formula (1a) or (1b), phosphonium salt of formula (2a) or (2b), and quaternary ammonium salt of formula (3a) or (3b), and conductive nano-material.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of thermoelectric conversion element.    Thermoelectric conversion element (1)    Metal plate (11)    Base materials (12, 16)    Electrodes (13, 15)    Thermoelectric conversion layer (14)