TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Compound: The single source precursor is liquid at room temperature; and is soluble in polar and non-polar organic solvents. The single source precursor yields I-III-(VI-2) ternary chalcopyrite material upon heating or pyrolysis of the single source precursor at a temperature less than 500degreesC; yields a ternary chalcopyrite material (preferably CuInS2) having a band gap of 1.5 eV between their conduction band and valence band; and yields a ternary chalcopyrite material (preferably CuGaS2) having a band gap of 2 eV between their conduction band and valence band. When the single source precursor yields a ternary chalcopyrite material having a band gap of 1.5 - 2 eV between their conduction band and valence band, then the ternary chalcopyrite material is Cu(In:Ga)(S:Se)2. When the single source precursor is (Ic) or (Id) and yields a ternary chalcopyrite material having a band gap of 2 - 2.4 eV between its conduction band and valence band, then the ternary chalcopyrite material is CuGaS2. In (m1), the single source precursor has three E-R groups. (Ia) Or (Ib) yields I-(III-5)-(VI-8) ternary chalcopyrite material upon heating or pyrolysis. When (Ic) or (Id) yields a ternary chalcopyrite material having a band gap of 0.5 - 3.5 eV between its conduction band and valence band, then the ternary chalcopyrite material is Cu:Ag:Au)1(Al:In:Ga)1(S:Se:Te)2. The single source precursor (I) is a compound of formula (Ia) - (Id).E1=Group VI-A atom (preferably S, Se or Te).Preferred Method: (m1) Involves providing a second single source precursor; and applying the first and second single source precursors on the substrate via the spray CVD technique. In (p1), the single source precursor is made in a single step consisting essentially of the reaction. The ionic complex (L(n)Ma(CH3CN)(4-n))+ is formed in situ as the reaction proceeds. The reaction is carried out under anaerobic or non-anaerobic conditions. The quantum dot made of a ternary I-III-(VI-2) chalcopyrite material; or ternary I-(III-5)-(VI-8) chalcopyrite material. The pyrolyzing step is carried out at a temperature less than 500degreesC. SPECIFIC COMPOUNDS - ((P(n-C4H9)3)2Cu(Se-C6H5)2In(Se-C6H5)2), ((P(n-C4H9)3)2Ag(S-C2H5)2In(S-C2H5)2), ((P(n-C4H9)3)2Cu(S-C2H5)2In(S-C2H5)2), ((P(n-C4H9)3)2Cu(S-C3H7)2In(S-C3H7)2) and ((P(C6H5)3)2Ag(S-CH3)2In(S-CH3)2) are specifically claimed as (I).    EXAMPLE - None given.