We wrote recently about several solar companies that had slipped in their timing to deliver new solar power technologies.

Konarka, a Lowell, Mass. company, is the latest example suggesting delay. The company uses organic plastics to create low-cost solar cells, has worked away for six years, chomped through $80 million, and has yet to produce its first commercial prototype. Now it is seeking $40 million in late-stage financing, according to VentureWire (subscription required).

In a statement earlier this week, it said chief executive Howard Berke was stepping down, to become executive chairman, while he joins a separate energy investment firm Good Energies, one of Konarka’s venture backers. President and Chief Operating Officer Rick Hess takes over as chief executive.

Backers include 3i, Draper Fisher Jurvetson, Good Energies, New Enterprise Associates, Partech International, Good Energies, Vanguard Ventures and Chevron Technology Ventures.