THE RESEARCH PROJECT UNDERTAKEN BY SIXTEEN AND SEVENTEEN YEAR OLD SCHOOL STUDENTS HAS BEEN CENTRED ON TWO SCHOOLS OVER THE LAST TWELVE MONTHS. THE WORK IS CARRIED OUT AT LUNCHTIMES AND AFTER SCHOOL, UNDER THE DIRECTION OF ONE OF THE SCIENCE TEACHERS.

AT SOUTH HUNSLEY SCHOOL ON HUMBERSIDE, THIN FILMS OF CADMIUM SULPHIDE HAVE BEEN PREPARED USING A MODIFIED PAINT SPRAY. THE FILMS PRODUCED HAVE PHOTOLUMINESCENT AND PHOTOCONDUCTIVE PROPERTIES NORMALLY ASSOCIATED WITH SINGLE CRYSTAL MATERIAL. MEROCYANINE DYES WERE THEN SPUNCOATED ON TOP OF THE CDS FILMS IN ORDER TO FORM A PHOTOVOLTAIC P-N HETEROJUNCTION.

STUDENTS AT TWYFORD CHURCH OF ENGLAND HIGH SCHOOL HAVE INVESTIGATED THE SUITABILITY OF A NUMBER OF MEROCYANINE DYES FOR THIS PURPOSE. ALL THE DYES CAN BE THOUGHT OF AS CONSISTING OF AN ELECTRON DONOR GROUP OF MOLECULES LINKED BY A BRIDGE TO AN ELECTRON ACCEPTOR GROUP. THE RESULTANT SOLAR CELLS HAVE BEEN EVALUATED IN TWO WAYS, VIZ. THE RELATIONSHIP BETWEEN CURRENT AND VOLTAGE UNDER MONOCHROMATIC ILLUMINATION AND THE VARIATION IN DEVICE CAPACITANCE WITH APPLIED VOLTAGE. MONOCHROMATIC ILLUMINATION WAS OBTAINED USING A SIMPLE SCHOOL SPECTROMETER "IN REVERSE".

INITIAL RESULTS HAVE ENABLED A TENTATIVE MODEL TO BE DRAWN UP FOR THE WAY IN WHICH THE CURRENT CARRIERS ARE PHOTOGENERATED IN SUCH JUNCTIONS. FURTHERMORE, THE STUDENTS HAVE BEEN ABLE TO DEVELOP A MATHEMATIC MODEL FOR PHOTOGENERATION, WHICH GIVES GOOD AGREEMENT WITH THE EXPERIMENTAL OBSERVATIONS. NEW APPARATUS, E.G. A C-V PLOTTER, HAVE BEEN CONSTRUCTED AND OTHER NORMAL SCHOOL LABORATORY EQUIPMENT, E.G. SPECTROMETER AND PAINT SPRAY, HAVE BEEN MODIFIED BY THE STUDENTS.