Rafael Robb, an economics professor originally from Israel, surrendered to authorities after being charged with first- and third-degree murder and possession of an instrument of crime.
Robb, 56, had told investigators he was in Philadelphia when his wife, Ellen, was killed Dec. 22 in the kitchen of their suburban home.
But prosecutors said his alibi did not hold up, and they had pressured him in recent days to prove his innocence.
Robb had said he took the couple's 12-year-old daughter to school that morning and last saw his wife alive at their Upper Merion Township home before driving to work at about 9:30 a.m.
District Attorney Bruce Castor said the crime scene was arranged to make it look as if Robb's wife, Ellen Robb, was killed during a burglary.
Robb "lied to the police about an obvious motive for this murder, his knowledge of his wife's recent plans to divorce him and obtain a significant portion of his wealth," police said in court papers.
He was arraigned on murder charges and jailed without bail.
Authorities said Ellen Robb's injuries were so extensive they initially thought she was killed with a shotgun blast to the face. The murder weapon has not been found.
Ellen Robb, 49, had told family members and others that she had hired a divorce attorney and was expecting $4,000 a month in spousal support after she moved out on Jan. 1, prosecutors said in court papers.
She was planning to move into a $1,500-per-month apartment by New Year's Day, the Philadelphia Enquirer reports.
Rafael Robblast week when he was questioned by a reporter outside the courthouse, where he was complying with a search warrant for blood and fingerprint samples.
Castor has previously described it as "an exceedingly bloody crime scene" and said the attack was not random.
"Mrs. Robb was the specific target of this assault," Castor said.
A window in a door had been smashed, but Castor said several pieces of evidence led authorities to believe the scene was staged to look like a burglary. For example, broken glass from the door window had not been crushed underfoot or tracked throughout the house, Castor said.
"That strikes me as very unusual," he said.
Castor also noted Rafael Robb has not reported anything missing from the house.
Investigators have taken forensic evidence from the Robbs' home — including computers and financial records — and searched the couple's cars and the professor's office at Penn, Castor said.
Montgomery County District Attorney Bruce Castor has said the murder scene was staged to look like a burglary.
Castor said investigators were interested in talking with members of the public who could discuss the professor's "personality, his habits, the way he interacts with people."
Shortly after Robb's wife was found dead, Robb's lawyer, Francis Genovese said: "It's not unusual in these investigations that they first start off closest to home. He is hopeful, as am I, that (authorities) are continuing to pursue all leads and not just focusing solely on him."
Robb has been at Penn for at least four years, according to a resume posted on his university Web site. Penn officials said earlier that they had arranged for someone else to teach Robb's graduate seminar in game theory this semester.
Game theory is used to understand consumer behavior. It is also used by military experts to develop nuclear warfare strategies.