(DE19533850-A1)      Photovoltaic cell has a charge transport layer contg. a hole conductor material (I). Also claimed is a method of making the cell.    Pref. the hole conductor is an amorphous material, consisting of spiro cpd(s). of formula (I), esp. 9,9'-spirobifluorene derivs. of formula (IA). Where U = Sn, pref. Ge, esp. Si or more esp. C; K1, K2 = conjugated systems. In (IA), the benzo gps. may be substd. and/or annelated.    USE -   The cell is used for generating current from sunlight (claimed).    ADVANTAGE -   In contrast to the electrolyte it replaces, the hole conductor material is not limited by ion diffusion. It decouples mass transport and charge transport.    (EP850492-A1)      Photovoltaic cell has a charge transport layer contg. a hole conductor material (I). Also claimed is a method of making the cell.    Pref. the hole conductor is an amorphous material, consisting of spiro cpd(s). of formula (I), esp. 9,9'-spirobifluorene derivs. of formula (IA). Where U = Sn, pref. Ge, esp. Si or more esp. C; K1, K2 = conjugated systems. In (IA), the benzo gps. may be substd. and/or annelated.    USE -   The cell is used for generating current from sunlight (claimed).    ADVANTAGE -   In contrast to the electrolyte it replaces, the hole conductor material is not limited by ion diffusion. It decouples mass transport and charge transport.    (US5885368-A)      Photovoltaic cell has a charge transport layer contg. a hole conductor material (I). Also claimed is a method of making the cell.    Pref. the hole conductor is an amorphous material, consisting of spiro cpd(s). of formula (I), esp. 9,9'-spirobifluorene derivs. of formula (IA). Where U = Sn, pref. Ge, esp. Si or more esp. C; K1, K2 = conjugated systems. In (IA), the benzo gps. may be substd. and/or annelated.    USE -   The cell is used for generating current from sunlight (claimed).    ADVANTAGE -   In contrast to the electrolyte it replaces, the hole conductor material is not limited by ion diffusion. It decouples mass transport and charge transport.    (JP11513522-W)      Photovoltaic cell has a charge transport layer contg. a hole conductor material (I). Also claimed is a method of making the cell.    Pref. the hole conductor is an amorphous material, consisting of spiro cpd(s). of formula (I), esp. 9,9'-spirobifluorene derivs. of formula (IA). Where U = Sn, pref. Ge, esp. Si or more esp. C; K1, K2 = conjugated systems. In (IA), the benzo gps. may be substd. and/or annelated.    USE -   The cell is used for generating current from sunlight (claimed).    ADVANTAGE -   In contrast to the electrolyte it replaces, the hole conductor material is not limited by ion diffusion. It decouples mass transport and charge transport.