That reign proved to be short-lived, as First Solar has produced an NREL-verified 18.7 percent cell out of its Perrysburg, Ohio factory and R&D center.

Keith Emery, who manages NREL's cell and module performance characterization group (and the cell efficiency records chart), confirms that the new First Solar cell arrived and was tested in mid-December.

In a statement coinciding with First Solar's 4Q12/FY 2012 financial results, company CTO Raffi Garabedian echoed what we heard from both GE and NREL last month: that there's still a lot of runway for thin-film solar PV technology, and particularly CdTe, to improve efficiency and its competitiveness with dominant crystalline silicon-based PV. "This achievement showcases the huge potential of CdTe compared to other PV technologies," he stated.

When GE announced its top CdTe mark, Anil Duggal, GE Research's solar technology platform leader, mused that CdTe cells ultimately could match the ~20 percent efficiency of today's multicrystalline silicon cells, and that GE's internal goal is 15 percent efficient CdTe modules.

First Solar emphasizes its cell was made using processes and materials "designed for commercial-scale manufacturing," including a glass substrate. The company, which also holds the NREL record for CdTe module efficiency (14.4 percent in January 2012), currently puts out modules with average conversion efficiency of 12.9 percent, and 13.1 percent in its best-producing line. During the company's 4Q12/FY12 results call this week, CFO Mark Widmar predicted that best-line module conversion efficiency would ratchet up by another full percentage point, and that adjusted efficiency and cost roadmaps would be released at its Analyst Day in April. (Somewhat controversially, First Solar also is postponing its 2013 guidance until that Analyst Day.)

Asked at the end of the call what's been behind First Solar's nearly one-and-a-half-point leap in module efficiency over the past year, CEO James Hughes again deferred to the upcoming Analyst Day for additional clarity. Here one might note that First Solar recently teamed up with Intermolecular (IM) to help accelerate its R&D learning curve, emphasizing materials innovation and process knob-tweaking. Intermolecular wouldn't comment on its ongoing work with this customer.