(ADPnews) - May 12, 2011 - German photovoltaic (PV) specialist Q-Cells SE (ETR:QCE) saw its revenue slump by 46% year-on-year to EUR 125.1 million (USD 177.2m) in the first quarter of 2011, driven down by the weak market demand and the uncertainty around regulatory changes for the solar sector in France and Italy.