NOVELTY - Modified surface (S1) comprises a surface containing an inorganic material, where an organic and/or organometallic compound is bound to the material and thereby modifies the surface to provide the modified surface, where the compound is a phosphinic acid compound.    USE - In a devices or device structures, batteries (claimed), photoelectric conversion devices, capacitors, electrochromic displays, chemical and/or biological sensors, light emitting diodes, electrodes, semiconductors, separation membranes, selective adsorbents, adsorbents for high-pressure liquid chromatography (HPLC), catalysts, implants, nanoparticles, antiadhesives, and anticorrosion coatings.    ADVANTAGE - The phosphinic acid group strongly binds to the metal oxide surface and is thus generally suitable for modifying a wide range of surfaces.    DETAILED DESCRIPTION - Modified surface comprises a surface containing an inorganic material, where an organic and/or organometallic compound is bound to the material and thereby modifies the surface to provide the modified surface, where the compound is a phosphinic acid compound of formula R1-P(=O)(R2)-OH (I).    R1 and R2=H, organic substituent or organometallic substituent.    Provided that at least one of R1 and R2 is not H. INDEPENDENT CLAIMS are included for the following:    (1) a device or device structure comprising the surface (S1), the device or structure being selected from a photoelectric conversion device, a battery, a capacitor, an electrochromic display, a chemical sensor, a biological sensor, a light emitting diode, an electrode, a semiconductor, a separation membrane, a selective adsorbant, an adsorbant for HPLC, a catalyst, an implant, a nanoparticle, an antiadhesive, and/or an anticorrosion coating;    (2) a battery comprising an electrode having the modified surface (S1);    (3) use of the compound (I) for use as a ligand in a organometallic dye;    (4) use of a phosphinic acid group for anchoring organic or organotetallic compounds on inorganic surfaces (preferably metal, oxide or sulfide surfaces); and    (5) a dye-sensitized solar cell comprising a semiconductor photoanode, where an organic or organometallic compound (1) is attached to the photoanode.